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How to Write a Literature Review | Guide, Examples, & Templates

Published on January 2, 2023 by Shona McCombes . Revised on September 11, 2023.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research that you can later apply to your paper, thesis, or dissertation topic .

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates, and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarize sources—it analyzes, synthesizes , and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

What is the purpose of a literature review, examples of literature reviews, step 1 – search for relevant literature, step 2 – evaluate and select sources, step 3 – identify themes, debates, and gaps, step 4 – outline your literature review’s structure, step 5 – write your literature review, free lecture slides, other interesting articles, frequently asked questions, introduction.

• Quick Run-through
• Step 1 & 2

When you write a thesis , dissertation , or research paper , you will likely have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and its scholarly context
• Develop a theoretical framework and methodology for your research
• Position your work in relation to other researchers and theorists
• Show how your research addresses a gap or contributes to a debate
• Evaluate the current state of research and demonstrate your knowledge of the scholarly debates around your topic.

Writing literature reviews is a particularly important skill if you want to apply for graduate school or pursue a career in research. We’ve written a step-by-step guide that you can follow below.

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See an example

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research problem and questions .

Make a list of keywords

Start by creating a list of keywords related to your research question. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list as you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some useful databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can also use boolean operators to help narrow down your search.

Make sure to read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

You likely won’t be able to read absolutely everything that has been written on your topic, so it will be necessary to evaluate which sources are most relevant to your research question.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models, and methods?
• Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible , and make sure you read any landmark studies and major theories in your field of research.

You can use our template to summarize and evaluate sources you’re thinking about using. Click on either button below to download.

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It is important to keep track of your sources with citations to avoid plagiarism . It can be helpful to make an annotated bibliography , where you compile full citation information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

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To begin organizing your literature review’s argument and structure, be sure you understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly visual platforms like Instagram and Snapchat—this is a gap that you could address in your own research.

There are various approaches to organizing the body of a literature review. Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarizing sources in order.

Try to analyze patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organize your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text , your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, you can follow these tips:

• Summarize and synthesize: give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: don’t just paraphrase other researchers — add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically evaluate: mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: use transition words and topic sentences to draw connections, comparisons and contrasts

In the conclusion, you should summarize the key findings you have taken from the literature and emphasize their significance.

When you’ve finished writing and revising your literature review, don’t forget to proofread thoroughly before submitting. Not a language expert? Check out Scribbr’s professional proofreading services !

This article has been adapted into lecture slides that you can use to teach your students about writing a literature review.

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If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Sampling methods
• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarize yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

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Review of Related Literature: Format, Example, & How to Make RRL

A review of related literature is a separate paper or a part of an article that collects and synthesizes discussion on a topic. Its purpose is to show the current state of research on the issue and highlight gaps in existing knowledge. A literature review can be included in a research paper or scholarly article, typically following the introduction and before the research methods section.

This article will clarify the definition, significance, and structure of a review of related literature. You’ll also learn how to organize your literature review and discover ideas for an RRL in different subjects.

🔤 What Is RRL?

• ❗ Significance of Literature Review
• 🔎 How to Search for Literature
• 🧩 Literature Review Structure
• 📋 Format of RRL — APA, MLA, & Others
• ✍️ How to Write an RRL
• 📚 Examples of RRL

🔗 References

A review of related literature (RRL) is a part of the research report that examines significant studies, theories, and concepts published in scholarly sources on a particular topic. An RRL includes 3 main components:

• A short overview and critique of the previous research.
• Similarities and differences between past studies and the current one.
• An explanation of the theoretical frameworks underpinning the research.

❗ Significance of Review of Related Literature

Although the goal of a review of related literature differs depending on the discipline and its intended use, its significance cannot be overstated. Here are some examples of how a review might be beneficial:

• It helps determine knowledge gaps .
• It saves from duplicating research that has already been conducted.
• It provides an overview of various research areas within the discipline.
• It demonstrates the researcher’s familiarity with the topic.

🔎 How to Perform a Literature Search

Including a description of your search strategy in the literature review section can significantly increase your grade. You can search sources with the following steps:

🧩 Literature Review Structure Example

The majority of literature reviews follow a standard introduction-body-conclusion structure. Let’s look at the RRL structure in detail.

Introduction of Review of Related Literature: Sample

An introduction should clarify the study topic and the depth of the information to be delivered. It should also explain the types of sources used. If your lit. review is part of a larger research proposal or project, you can combine its introductory paragraph with the introduction of your paper.

Here is a sample introduction to an RRL about cyberbullying:

Bullying has troubled people since the beginning of time. However, with modern technological advancements, especially social media, bullying has evolved into cyberbullying. As a result, nowadays, teenagers and adults cannot flee their bullies, which makes them feel lonely and helpless. This literature review will examine recent studies on cyberbullying.

Sample Review of Related Literature Thesis

A thesis statement should include the central idea of your literature review and the primary supporting elements you discovered in the literature. Thesis statements are typically put at the end of the introductory paragraph.

Look at a sample thesis of a review of related literature:

This literature review shows that scholars have recently covered the issues of bullies’ motivation, the impact of bullying on victims and aggressors, common cyberbullying techniques, and victims’ coping strategies. However, there is still no agreement on the best practices to address cyberbullying.

Literature Review Body Paragraph Example

The main body of a literature review should provide an overview of the existing research on the issue. Body paragraphs should not just summarize each source but analyze them. You can organize your paragraphs with these 3 elements:

• Claim . Start with a topic sentence linked to your literature review purpose.
• Evidence . Cite relevant information from your chosen sources.
• Discussion . Explain how the cited data supports your claim.

Here’s a literature review body paragraph example:

Scholars have examined the link between the aggressor and the victim. Beran et al. (2007) state that students bullied online often become cyberbullies themselves. Faucher et al. (2014) confirm this with their findings: they discovered that male and female students began engaging in cyberbullying after being subject to bullying. Hence, one can conclude that being a victim of bullying increases one’s likelihood of becoming a cyberbully.

Review of Related Literature: Conclusion

A conclusion presents a general consensus on the topic. Depending on your literature review purpose, it might include the following:

• Introduction to further research . If you write a literature review as part of a larger research project, you can present your research question in your conclusion .
• Overview of theories . You can summarize critical theories and concepts to help your reader understand the topic better.
• Discussion of the gap . If you identified a research gap in the reviewed literature, your conclusion could explain why that gap is significant.

Check out a conclusion example that discusses a research gap:

There is extensive research into bullies’ motivation, the consequences of bullying for victims and aggressors, strategies for bullying, and coping with it. Yet, scholars still have not reached a consensus on what to consider the best practices to combat cyberbullying. This question is of great importance because of the significant adverse effects of cyberbullying on victims and bullies.

📋 Format of RRL — APA, MLA, & Others

In this section, we will discuss how to format an RRL according to the most common citation styles: APA, Chicago, MLA, and Harvard.

Writing a literature review using the APA7 style requires the following text formatting:

• When using APA in-text citations , include the author’s last name and the year of publication in parentheses.
• For direct quotations , you must also add the page number. If you use sources without page numbers, such as websites or e-books, include a paragraph number instead.
• When referring to the author’s name in a sentence , you do not need to repeat it at the end of the sentence. Instead, include the year of publication inside the parentheses after their name.
• The reference list should be included at the end of your literature review. It is always alphabetized by the last name of the author (from A to Z), and the lines are indented one-half inch from the left margin of your paper. Do not forget to invert authors’ names (the last name should come first) and include the full titles of journals instead of their abbreviations. If you use an online source, add its URL.

The RRL format in the Chicago style is as follows:

• Author-date . You place your citations in brackets within the text, indicating the name of the author and the year of publication.
• Notes and bibliography . You place your citations in numbered footnotes or endnotes to connect the citation back to the source in the bibliography.
• The reference list, or bibliography , in Chicago style, is at the end of a literature review. The sources are arranged alphabetically and single-spaced. Each bibliography entry begins with the author’s name and the source’s title, followed by publication information, such as the city of publication, the publisher, and the year of publication.

Writing a literature review using the MLA style requires the following text formatting:

• In the MLA format, you can cite a source in the text by indicating the author’s last name and the page number in parentheses at the end of the citation. If the cited information takes several pages, you need to include all the page numbers.
• The reference list in MLA style is titled “ Works Cited .” In this section, all sources used in the paper should be listed in alphabetical order. Each entry should contain the author, title of the source, title of the journal or a larger volume, other contributors, version, number, publisher, and publication date.

The Harvard style requires you to use the following text formatting for your RRL:

• In-text citations in the Harvard style include the author’s last name and the year of publication. If you are using a direct quote in your literature review, you need to add the page number as well.
• Arrange your list of references alphabetically. Each entry should contain the author’s last name, their initials, the year of publication, the title of the source, and other publication information, like the journal title and issue number or the publisher.

✍️ How to Write Review of Related Literature – Sample

Literature reviews can be organized in many ways depending on what you want to achieve with them. In this section, we will look at 3 examples of how you can write your RRL.

Thematic Literature Review

A thematic literature review is arranged around central themes or issues discussed in the sources. If you have identified some recurring themes in the literature, you can divide your RRL into sections that address various aspects of the topic. For example, if you examine studies on e-learning, you can distinguish such themes as the cost-effectiveness of online learning, the technologies used, and its effectiveness compared to traditional education.

Chronological Literature Review

A chronological literature review is a way to track the development of the topic over time. If you use this method, avoid merely listing and summarizing sources in chronological order. Instead, try to analyze the trends, turning moments, and critical debates that have shaped the field’s path. Also, you can give your interpretation of how and why specific advances occurred.

Methodological Literature Review

A methodological literature review differs from the preceding ones in that it usually doesn’t focus on the sources’ content. Instead, it is concerned with the research methods . So, if your references come from several disciplines or fields employing various research techniques, you can compare the findings and conclusions of different methodologies, for instance:

• empirical vs. theoretical studies;
• qualitative vs. quantitative research.

📚 Examples of Review of Related Literature and Studies

We have prepared a short example of RRL on climate change for you to see how everything works in practice!

Climate change is one of the most important issues nowadays. Based on a variety of facts, it is now clearer than ever that humans are altering the Earth's climate. The atmosphere and oceans have warmed, causing sea level rise, a significant loss of Arctic ice, and other climate-related changes. This literature review provides a thorough summary of research on climate change, focusing on climate change fingerprints and evidence of human influence on the Earth's climate system.

Physical Mechanisms and Evidence of Human Influence

Scientists are convinced that climate change is directly influenced by the emission of greenhouse gases. They have carefully analyzed various climate data and evidence, concluding that the majority of the observed global warming over the past 50 years cannot be explained by natural factors alone. Instead, there is compelling evidence pointing to a significant contribution of human activities, primarily the emission of greenhouse gases (Walker, 2014). For example, based on simple physics calculations, doubled carbon dioxide concentration in the atmosphere can lead to a global temperature increase of approximately 1 degree Celsius. (Elderfield, 2022). In order to determine the human influence on climate, scientists still have to analyze a lot of natural changes that affect temperature, precipitation, and other components of climate on timeframes ranging from days to decades and beyond.

Fingerprinting Climate Change

Fingerprinting climate change is a useful tool to identify the causes of global warming because different factors leave unique marks on climate records. This is evident when scientists look beyond overall temperature changes and examine how warming is distributed geographically and over time (Watson, 2022). By investigating these climate patterns, scientists can obtain a more complex understanding of the connections between natural climate variability and climate variability caused by human activity.

Modeling Climate Change and Feedback

To accurately predict the consequences of feedback mechanisms, the rate of warming, and regional climate change, scientists can employ sophisticated mathematical models of the atmosphere, ocean, land, and ice (the cryosphere). These models are grounded in well-established physical laws and incorporate the latest scientific understanding of climate-related processes (Shuckburgh, 2013). Although different climate models produce slightly varying projections for future warming, they all will agree that feedback mechanisms play a significant role in amplifying the initial warming caused by greenhouse gas emissions. (Meehl, 2019).

In conclusion, the literature on global warming indicates that there are well-understood physical processes that link variations in greenhouse gas concentrations to climate change. In addition, it covers the scientific proof that the rates of these gases in the atmosphere have increased and continue to rise fast. According to the sources, the majority of this recent change is almost definitely caused by greenhouse gas emissions produced by human activities. Citizens and governments can alter their energy production methods and consumption patterns to reduce greenhouse gas emissions and, thus, the magnitude of climate change. By acting now, society can prevent the worst consequences of climate change and build a more resilient and sustainable future for generations to come.

Have you ever struggled with finding the topic for an RRL in different subjects? Read the following paragraphs to get some ideas!

Nursing Literature Review Example

Many topics in the nursing field require research. For example, you can write a review of literature related to dengue fever . Give a general overview of dengue virus infections, including its clinical symptoms, diagnosis, prevention, and therapy.

Another good idea is to review related literature and studies about teenage pregnancy . This review can describe the effectiveness of specific programs for adolescent mothers and their children and summarize recommendations for preventing early pregnancy.

📝 Check out some more valuable examples below:

• Hospital Readmissions: Literature Review .
• Literature Review: Lower Sepsis Mortality Rates .
• Breast Cancer: Literature Review .
• Sexually Transmitted Diseases: Literature Review .
• PICO for Pressure Ulcers: Literature Review .
• COVID-19 Spread Prevention: Literature Review .
• Chronic Obstructive Pulmonary Disease: Literature Review .
• Hypertension Treatment Adherence: Literature Review .
• Neonatal Sepsis Prevention: Literature Review .
• Healthcare-Associated Infections: Literature Review .
• Understaffing in Nursing: Literature Review .

Psychology Literature Review Example

If you look for an RRL topic in psychology , you can write a review of related literature about stress . Summarize scientific evidence about stress stages, side effects, types, or reduction strategies. Or you can write a review of related literature about computer game addiction . In this case, you may concentrate on the neural mechanisms underlying the internet gaming disorder, compare it to other addictions, or evaluate treatment strategies.

A review of related literature about cyberbullying is another interesting option. You can highlight the impact of cyberbullying on undergraduate students’ academic, social, and emotional development.

📝 Look at the examples that we have prepared for you to come up with some more ideas:

• Mindfulness in Counseling: A Literature Review .
• Team-Building Across Cultures: Literature Review .
• Anxiety and Decision Making: Literature Review .
• Literature Review on Depression .
• Literature Review on Narcissism .
• Effects of Depression Among Adolescents .
• Causes and Effects of Anxiety in Children .

Literature Review — Sociology Example

Sociological research poses critical questions about social structures and phenomena. For example, you can write a review of related literature about child labor , exploring cultural beliefs and social norms that normalize the exploitation of children. Or you can create a review of related literature about social media . It can investigate the impact of social media on relationships between adolescents or the role of social networks on immigrants’ acculturation .

📝 You can find some more ideas below!

• Single Mothers’ Experiences of Relationships with Their Adolescent Sons .
• Teachers and Students’ Gender-Based Interactions .
• Gender Identity: Biological Perspective and Social Cognitive Theory .
• Gender: Culturally-Prescribed Role or Biological Sex .
• The Influence of Opioid Misuse on Academic Achievement of Veteran Students .
• The Importance of Ethics in Research .
• The Role of Family and Social Network Support in Mental Health .

Education Literature Review Example

For your education studies , you can write a review of related literature about academic performance to determine factors that affect student achievement and highlight research gaps. One more idea is to create a review of related literature on study habits , considering their role in the student’s life and academic outcomes.

You can also evaluate a computerized grading system in a review of related literature to single out its advantages and barriers to implementation. Or you can complete a review of related literature on instructional materials to identify their most common types and effects on student achievement.

📝 Find some inspiration in the examples below:

• Literature Review on Online Learning Challenges From COVID-19 .
• Education, Leadership, and Management: Literature Review .
• Literature Review: Standardized Testing Bias .
• Bullying of Disabled Children in School .
• Interventions and Letter & Sound Recognition: A Literature Review .
• Social-Emotional Skills Program for Preschoolers .
• Effectiveness of Educational Leadership Management Skills .

Business Research Literature Review

If you’re a business student, you can focus on customer satisfaction in your review of related literature. Discuss specific customer satisfaction features and how it is affected by service quality and prices. You can also create a theoretical literature review about consumer buying behavior to evaluate theories that have significantly contributed to understanding how consumers make purchasing decisions.

📝 Look at the examples to get more exciting ideas:

• Leadership and Communication: Literature Review .
• Human Resource Development: Literature Review .
• Project Management. Literature Review .
• Strategic HRM: A Literature Review .
• Customer Relationship Management: Literature Review .
• Literature Review on International Financial Reporting Standards .
• Cultures of Management: Literature Review .

To conclude, a review of related literature is a significant genre of scholarly works that can be applied in various disciplines and for multiple goals. The sources examined in an RRL provide theoretical frameworks for future studies and help create original research questions and hypotheses.

When you finish your outstanding literature review, don’t forget to check whether it sounds logical and coherent. Our text-to-speech tool can help you with that!

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How to Write Review of Related Literature (RRL) in Research

A review of related literature (a.k.a RRL in research) is a comprehensive review of the existing literature pertaining to a specific topic or research question. An effective review provides the reader with an organized analysis and synthesis of the existing knowledge about a subject. With the increasing amount of new information being disseminated every day, conducting a review of related literature is becoming more difficult and the purpose of review of related literature is clearer than ever.  

All new knowledge is necessarily based on previously known information, and every new scientific study must be conducted and reported in the context of previous studies. This makes a review of related literature essential for research, and although it may be tedious work at times , most researchers will complete many such reviews of varying depths during their career. So, why exactly is a review of related literature important?    

Table of Contents

Why a review of related literature in research is important  

Before thinking how to do reviews of related literature , it is necessary to understand its importance. Although the purpose of a review of related literature varies depending on the discipline and how it will be used, its importance is never in question. Here are some ways in which a review can be crucial.  

• Identify gaps in the knowledge – This is the primary purpose of a review of related literature (often called RRL in research ). To create new knowledge, you must first determine what knowledge may be missing. This also helps to identify the scope of your study.  
• Avoid duplication of research efforts – Not only will a review of related literature indicate gaps in the existing research, but it will also lead you away from duplicating research that has already been done and thus save precious resources.  
• Provide an overview of disparate and interdisciplinary research areas – Researchers cannot possibly know everything related to their disciplines. Therefore, it is very helpful to have access to a review of related literature already written and published.  
• Highlight researcher’s familiarity with their topic 1  – A strong review of related literature in a study strengthens readers’ confidence in that study and that researcher.

Tips on how to write a review of related literature in research

Given that you will probably need to produce a number of these at some point, here are a few general tips on how to write an effective review of related literature 2 .

• Define your topic, audience, and purpose: You will be spending a lot of time with this review, so choose a topic that is interesting to you. While deciding what to write in a review of related literature , think about who you expect to read the review – researchers in your discipline, other scientists, the general public – and tailor the language to the audience. Also, think about the purpose of your review of related literature .  
• Conduct a comprehensive literature search: While writing your review of related literature , emphasize more recent works but don’t forget to include some older publications as well. Cast a wide net, as you may find some interesting and relevant literature in unexpected databases or library corners. Don’t forget to search for recent conference papers.
• Review the identified articles and take notes: It is a good idea to take notes in a way such that individual items in your notes can be moved around when you organize them. For example, index cards are great tools for this. Write each individual idea on a separate card along with the source. The cards can then be easily grouped and organized.  
• Determine how to organize your review: A review of related literature should not be merely a listing of descriptions. It should be organized by some criterion, such as chronologically or thematically.  
• Be critical and objective: Don’t just report the findings of other studies in your review of related literature . Challenge the methodology, find errors in the analysis, question the conclusions. Use what you find to improve your research. However, do not insert your opinions into the review of related literature. Remain objective and open-minded.  
• Structure your review logically: Guide the reader through the information. The structure will depend on the function of the review of related literature. Creating an outline prior to writing the RRL in research is a good way to ensure the presented information flows well.  

As you read more extensively in your discipline, you will notice that the review of related literature appears in various forms in different places. For example, when you read an article about an experimental study, you will typically see a literature review or a RRL in research , in the introduction that includes brief descriptions of similar studies. In longer research studies and dissertations, especially in the social sciences, the review of related literature will typically be a separate chapter and include more information on methodologies and theory building. In addition, stand-alone review articles will be published that are extremely useful to researchers.  

The review of relevant literature or often abbreviated as, RRL in research , is an important communication tool that can be used in many forms for many purposes. It is a tool that all researchers should befriend.  

• University of North Carolina at Chapel Hill Writing Center. Literature Reviews.  https://writingcenter.unc.edu/tips-and-tools/literature-reviews/  [Accessed September 8, 2022]
• Pautasso M. Ten simple rules for writing a literature review. PLoS Comput Biol. 2013, 9. doi: 10.1371/journal.pcbi.1003149.

Q:  Is research complete without a review of related literature?

A research project is usually considered incomplete without a proper review of related literature. The review of related literature is a crucial component of any research project as it provides context for the research question, identifies gaps in existing literature, and ensures novelty by avoiding duplication. It also helps inform research design and supports arguments, highlights the significance of a study, and demonstrates your knowledge an expertise.

Q: What is difference between RRL and RRS?

The key difference between an RRL and an RRS lies in their focus and scope. An RRL or review of related literature examines a broad range of literature, including theoretical frameworks, concepts, and empirical studies, to establish the context and significance of the research topic. On the other hand, an RRS or review of research studies specifically focuses on analyzing and summarizing previous research studies within a specific research domain to gain insights into methodologies, findings, and gaps in the existing body of knowledge. While there may be some overlap between the two, they serve distinct purposes and cover different aspects of the research process.

Q: Does review of related literature improve accuracy and validity of research?

Yes, a comprehensive review of related literature (RRL) plays a vital role in improving the accuracy and validity of research. It helps authors gain a deeper understanding and offers different perspectives on the research topic. RRL can help you identify research gaps, dictate the selection of appropriate research methodologies, enhance theoretical frameworks, avoid biases and errors, and even provide support for research design and interpretation. By building upon and critically engaging with existing related literature, researchers can ensure their work is rigorous, reliable, and contributes meaningfully to their field of study.

R Discovery is a literature search and research reading platform that accelerates your research discovery journey by keeping you updated on the latest, most relevant scholarly content. With 250M+ research articles sourced from trusted aggregators like CrossRef, Unpaywall, PubMed, PubMed Central, Open Alex and top publishing houses like Springer Nature, JAMA, IOP, Taylor & Francis, NEJM, BMJ, Karger, SAGE, Emerald Publishing and more, R Discovery puts a world of research at your fingertips.  

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• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

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Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
• Critically evaluate: mention the strengths and weaknesses of your sources.
• Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

Cite this Scribbr article

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Literature review

How to write a literature review in 6 steps

How do you write a good literature review? This step-by-step guide on how to write an excellent literature review covers all aspects of planning and writing literature reviews for academic papers and theses.

How to write a systematic literature review [9 steps]

How do you write a systematic literature review? What types of systematic literature reviews exist and where do you use them? Learn everything you need to know about a systematic literature review in this guide

What is a literature review? [with examples]

Not sure what a literature review is? This guide covers the definition, purpose, and format of a literature review.

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• 04 December 2020
• Correction 09 December 2020

How to write a superb literature review

Andy Tay is a freelance writer based in Singapore.

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Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

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Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

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Ledesma, H. A. et al. Nature Nanotechnol. 14 , 645–657 (2019).

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A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE: Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

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Review of Related Literature (RRL)

Ai generator.

The Review of Related Literature (RRL) is a crucial section in research that examines existing studies and publications related to a specific topic. It summarizes and synthesizes previous findings, identifies gaps, and provides context for the current research. RRL ensures the research is grounded in established knowledge, guiding the direction and focus of new studies.

What Is Review of Related Literature (RRL)?

The Review of Related Literature (RRL) is a detailed analysis of existing research relevant to a specific topic. It evaluates, synthesizes, and summarizes previous studies to identify trends, gaps, and conflicts in the literature. RRL provides a foundation for new research, ensuring it builds on established knowledge and addresses existing gaps.

Format of Review of Related Literature (RRL)

The Review of Related Literature (RRL) is a critical part of any research paper or thesis . It provides an overview of existing research on your topic and helps to establish the context for your study. Here is a typical format for an RRL:

1. Introduction

• Purpose : Explain the purpose of the review and its importance to your research.
• Scope : Define the scope of the literature reviewed, including the time frame, types of sources, and key themes.

2. Theoretical Framework

• Concepts and Theories : Present the main theories and concepts that underpin your research.
• Relevance : Explain how these theories relate to your study.

3. Review of Empirical Studies

• Sub-theme 1 : Summarize key studies, including methodologies, findings, and conclusions.
• Sub-theme 2 : Continue summarizing studies, focusing on different aspects or variables.
• Sub-theme 3 : Include any additional relevant studies.

4. Methodological Review

• Approaches : Discuss the various methodologies used in the reviewed studies.
• Strengths and Weaknesses : Highlight the strengths and weaknesses of these methodologies.
• Gaps : Identify gaps in the existing research that your study aims to address.

5. Synthesis and Critique

• Integration : Integrate findings from the reviewed studies to show the current state of knowledge.
• Critique : Critically evaluate the literature, discussing inconsistencies, limitations, and areas for further research.

6. Conclusion

• Summary : Summarize the main findings from the literature review.
• Research Gap : Clearly state the research gap your study will address.
• Contribution : Explain how your study will contribute to the existing body of knowledge.

7. References

• Citation Style : List all the sources cited in your literature review in the appropriate citation style (e.g., APA, MLA, Chicago).

Review of Related Literature (RRL) 1. Introduction This review examines research on social media’s impact on mental health, focusing on anxiety and depression across various demographics over the past ten years. 2. Theoretical Framework Anchored in Social Comparison Theory and Uses and Gratifications Theory, this review explores how individuals’ social media interactions affect their mental health. 3. Review of Empirical Studies Adolescents’ Mental Health Instagram & Body Image : Smith & Johnson (2017) found Instagram use linked to body image issues and lower self-esteem among 500 high school students. Facebook & Anxiety : Brown & Green (2016) showed Facebook use correlated with higher anxiety and depressive symptoms in a longitudinal study of 300 students. Young Adults’ Mental Health Twitter & Stress : Davis & Lee (2018) reported higher stress levels among heavy Twitter users in a survey of 400 university students. LinkedIn & Self-Esteem : Miller & White (2019) found LinkedIn use positively influenced professional self-esteem in 200 young professionals. Adult Mental Health General Social Media Use : Thompson & Evans (2020) found moderate social media use associated with better mental health outcomes, while excessive use correlated with higher anxiety and depression in 1,000 adults. 4. Methodological Review Studies used cross-sectional surveys, longitudinal designs, and mixed methods. Cross-sectional surveys provided large data sets but couldn’t infer causation. Longitudinal studies offered insights into long-term effects but were resource-intensive. Mixed methods enriched data through qualitative insights but required careful integration. 5. Synthesis and Critique The literature shows a complex relationship between social media and mental health, with platform-specific and demographic-specific effects. However, reliance on self-reported data introduces bias, and many cross-sectional studies limit causal inference. More longitudinal and experimental research is needed. 6. Conclusion Current research offers insights into social media’s mental health impact but leaves gaps, particularly regarding long-term effects and causation. This study aims to address these gaps through comprehensive longitudinal analysis. 7. References Brown, A., & Green, K. (2016). Facebook Use and Anxiety Among High School Students . Psychology in the Schools, 53(3), 257-264. Davis, R., & Lee, S. (2018). Twitter and Psychological Stress: A Study of University Students . Journal of College Student Development, 59(2), 120-135. Miller, P., & White, H. (2019). LinkedIn and Its Effect on Professional Self-Esteem . Journal of Applied Psychology, 104(1), 78-90. Smith, J., & Johnson, L. (2017). The Impact of Instagram on Teen Body Image . Journal of Adolescent Health, 60(5), 555-560. Thompson, M., & Evans, D. (2020). The Relationship Between Social Media Use and Mental Health in Adults . Cyberpsychology, Behavior, and Social Networking, 23(4), 201-208.

Review of Related Literature (RRL) Examples

Review of related literature in research, review of related literature in research paper, review of related literature qualitative research.

Review of Related Literature Quantitative Research

More Review of Related Literature (RRL) Examples

• Impact of E-learning on Student Performance
• Effectiveness of Mindfulness in Workplace
• Green Building and Energy Efficiency
• Impact of Technology on Healthcare Delivery
• Effects of Nutrition on Cognitive Development in Children
• Impact of Employee Training Programs on Productivity
• Effects of Climate Change on Biodiversity
• Impact of Parental Involvement on Student Achievement
• Effects of Mobile Learning on Student Engagement
• Effects of Urban Green Spaces on Mental Health

Purpose of the Review of Related Literature (RRL)

The Review of Related Literature (RRL) serves several critical purposes in research:

• Establishing Context : It situates your research within the broader field, showing how your study relates to existing work.
• Identifying Gaps : It highlights gaps, inconsistencies, and areas needing further exploration in current knowledge, providing a clear rationale for your study.
• Avoiding Duplication : By reviewing what has already been done, it helps ensure your research is original and not a repetition of existing studies.
• Building on Existing Knowledge : It allows you to build on the findings of previous research, using established theories and methodologies to inform your work.
• Theoretical Foundation : It provides a theoretical basis for your research, grounding it in existing concepts and theories.
• Methodological Insights : It offers insights into the methods and approaches used in similar studies, helping you choose the most appropriate methods for your research.
• Establishing Credibility : It demonstrates your familiarity with the field, showing that you are well-informed and have a solid foundation for your research.
• Supporting Arguments : It provides evidence and support for your research questions, hypotheses, and objectives, strengthening the overall argument of your study.

How to Write Review of Related Literature (RRL)

Writing a Review of Related Literature (RRL) involves several key steps. Here’s a step-by-step guide:

1. Define the Scope and Objectives

• Determine the Scope : Decide on the breadth of the literature you will review, including specific themes, time frame, and types of sources.
• Set Objectives : Clearly define the purpose of the review. What do you aim to achieve? Identify gaps, establish context, or build on existing knowledge.

2. Search for Relevant Literature

• Identify Keywords : Use keywords and phrases related to your research topic.
• Use Databases : Search academic databases like Google Scholar, PubMed, JSTOR, etc., for relevant articles, books, and papers.
• Select Sources : Choose sources that are credible, recent, and relevant to your research.

3. Evaluate and Select the Literature

• Read Abstracts and Summaries : Quickly determine the relevance of each source.
• Assess Quality : Consider the methodology, credibility of the authors, and publication source.
• Select Key Studies : Choose studies that are most relevant to your research questions and objectives.

4. Organize the Literature

• Thematic Organization : Group studies by themes or topics.
• Chronological Organization : Arrange studies in the order they were published to show the development of ideas over time.
• Methodological Organization : Categorize studies by the methods they used.

5. Write the Review

• State the purpose and scope of the review.
• Explain the importance of the topic.
• Theoretical Framework : Present and discuss the main theories and concepts.
• Summarize key studies, including their methodologies, findings, and conclusions.
• Organize by themes or other chosen organizational methods.
• Methodological Review : Discuss the various methodologies used, highlighting their strengths and weaknesses.
• Synthesis and Critique : Integrate findings, critically evaluate the literature, and identify gaps or inconsistencies.
• Summarize the main findings from the literature review.
• Highlight the research gaps your study will address.
• State how your research will contribute to the existing knowledge.

6. Cite the Sources

• Use Appropriate Citation Style : Follow the required citation style (e.g., APA, MLA, Chicago).
• List References : Provide a complete list of all sources cited in your review.

What is an RRL?

An RRL summarizes and synthesizes existing research on a specific topic to identify gaps and guide future studies.

Why is RRL important?

It provides context, highlights gaps, and ensures new research builds on existing knowledge.

How do you write an RRL?

Organize by themes, summarize studies, evaluate methodologies, identify gaps, and conclude with relevance to current research.

What sources are used in RRL?

Peer-reviewed journals, books, conference papers, and credible online resources.

How long should an RRL be?

Length varies; typically 10-20% of the total research paper.

What are common RRL mistakes?

Lack of organization, insufficient synthesis, over-reliance on outdated sources, and failure to identify gaps.

Can an RRL include non-scholarly sources?

Primarily scholarly, but reputable non-scholarly sources can be included for context.

What is the difference between RRL and bibliography?

RRL synthesizes and analyzes the literature, while a bibliography lists sources.

How often should an RRL be updated?

Regularly, especially when new relevant research is published.

Can an RRL influence research direction?

Yes, it identifies gaps and trends that shape the focus and methodology of new research.

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Ten Simple Rules for Writing a Literature Review

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1 Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France

2 Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

Funding Statement

This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

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Related work / literature review / research review, download pdf handout:   literature reviews, watch video:   literature reviews.

A  literature review, research review,  or  related work   section compares, contrasts, synthesizes, and provides introspection about the available knowledge for a given topic or field. The two terms are sometimes used interchangeably (as they are here), but while both can refer to a section of a longer work, “literature review” can also describe a stand-alone paper.

When you start writing a literature review, the most straightforward course may be to compile all relevant sources and compare them, perhaps evaluating their strengths and weaknesses. While this is a good place to start, your literature review is incomplete unless it creates something new through these comparisons. Luckily, our resources can help you do this!

With these resources, you’ll learn:

• How to write a literature review that  contributes  rather than  summarizes
• Common mistakes to avoid
• Useful phrases to show agreement and disagreement between sources

Need one-on-one help with your literature review or research article? Schedule an appointment with one of our consultants now!

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Literature Review: Conducting & Writing

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You can sort the literature in various ways, for example:

How to Begin?

Read your sources carefully and find the main idea(s) of each source

Look for similarities in your sources – which sources are talking about the same main ideas? (for example, sources that discuss the historical background on your topic)

Use the worksheet (above) or synthesis matrix (below) to get organized

This work can be messy. Don't worry if you have to go through a few iterations of the worksheet or matrix as you work on your lit review!

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Research Effectively: Tips on How to Review Related Literature

• Peer Review

Professors across various disciplines require their students to write literature reviews. This article provides pertinent information on how to review related literature effectively.

Updated on December 1, 2021

Professors across various disciplines require their students to write literature reviews, which are collections of authoritative sources on particular topics. They are an essential part of research, because it provides a handy guide to more information on their subjects.

This article provides pertinent information on how to review related literature effectively. By learning these techniques, you may improve your teaching skills and become more effective at grant writing.

Before you start writing, keep in mind that you may need a good management cloud service to store all your files when reviewing your related literature. And once you're done writing your research paper, you may want to promote it using different SEO strategies .

Tips on How to Review Related Literature Effectively

Evaluate the resources.

Make sure to constantly evaluate the sources that your students have incorporated into their literature review. Also, verify whether the resources contain valuable and pertinent information regarding their chosen topic.

Evaluating the resources is particularly vital when an academic library does not collect the sources your students have retrieved.

Web resources may be easily accessible. However, students and professors alike must be more careful to ensure that the sources gathered are reliable.

Below are five essential criteria to help you evaluate information from any resource:

Evaluation Criteria

1. accuracy.

The information from the sources your students gathered must be error-free to ensure its reliability. Furthermore, the details must be based on proven facts. To help you check whether the information is factual or not, you may need to verify it against other authoritative sources.

2. Authority

Check the authors' backgrounds. Authors of scholarly journals must have the qualifications to write on a specific topic. In addition, they must be affiliated with an established organization or a reputable university in the subject field.

3. Objectivity

Carefully examine the intended purpose of the information. It must be based on facts and not merely opinions. Thus, the details in the study must be impartial.

4. Currency

It's also necessary to check the currency of the sources. Are the pieces of information still current, or are they outdated? A good rule of thumb is to utilize sources published in the past ten years for research papers in the humanities, history, arts, and literature.

For fast-paced fields like the sciences, resources published in the past two to three years are a good benchmark since they are more current. Thus, they reflect the newest discoveries, best practices, theories, and processes.

5. Coverage

Make sure to verify whether you or your students' resources have met your information needs. After reading their output, ask yourself if the material they used gave in-depth coverage or just basic information.

Know the Ideal Types of Periodicals for Literature Reviews

Scholarly journals.

A literature review is composed of various scholarly works. Aside from theses and dissertations, academic journals are essential resources that your students can incorporate in their literature reviews.

The authors of scholarly journals are scholars, researchers, and subject experts. The findings in the academic paper are based on in-depth analysis and stated methodology.

Most of the time, the authors use discipline-specific terminology and jargon that may be difficult to comprehend.

Scholarly journals also have references cited in footnotes or bibliographies. The frequency of their publication may be quarterly, monthly, or annually. Some advertise, but many do not.

Trade Magazines

Trade magazines are authored by paid staff with subject expertise and are members of a particular industry.

Their content is about trends, current news, products, and developments in specific fields. Like scholarly journals, authors of trade magazines also use industry-specific jargon. However, peer reviewers don't assess the quality of trade magazines. In addition, these periodicals also have several advertisements that are usually industry related.

Trade magazines may have valuable information. Still, it's best to use scholarly journals in literature reviews. With academic journals, you can be surer of the quality of the paper since they're peer-reviewed.

Popular Magazines and Newspapers

These are non-authoritative sources. Paid staff, who are often non-experts, write these types of periodicals. They're composed heavily of advertisements and are published daily, weekly, or monthly. These could be useful in literature reviews, but also keep in mind that they may be viewed as less credible, because they're often written by non-experts. [Ed1]

Evaluate Different Websites

The internet is a vast network of unfiltered sources, which means anyone can put anything in it, bypassing any form of editorial or peer review. Therefore, it is of utmost importance that you evaluate the web sources you and your students use before including them in your scholarly publication.

Always look for the authors' information. Check the links that read “About this site” and “Who we are.” In addition, verify whether the webmaster provides contact information so that you can contact them with inquiries.

Lastly, look for hints on authority in the internet address (URL).

• .com is a commercial site
• .gov is a government agency or department
• .net is a network provider
• .org is a non-profit organization that may either be biased or unbiased
• .edu is an educational institution

Writing a literature review aims to convey what knowledge has been established on a particular topic, as well as the strengths and weaknesses[Ed2] of the information out there among the resources.

Knowing the essential information on how to review related literature is beneficial to you and your students.

Being aware of these techniques may help you alleviate your students' anxiety about literature reviews and solidify your status as an excellent teacher.

After you've found written your research paper from reliable sources, consider letting our team PhD editors go over your research paper with our Premium English Editing service .

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How To Structure Your Literature Review

3 options to help structure your chapter.

By: Amy Rommelspacher (PhD) | Reviewer: Dr Eunice Rautenbach | November 2020 (Updated May 2023)

Writing the literature review chapter can seem pretty daunting when you’re piecing together your dissertation or thesis. As  we’ve discussed before , a good literature review needs to achieve a few very important objectives – it should:

• Demonstrate your knowledge of the research topic
• Identify the gaps in the literature and show how your research links to these
• Provide the foundation for your conceptual framework (if you have one)
• Inform your own  methodology and research design

To achieve this, your literature review needs a well-thought-out structure . Get the structure of your literature review chapter wrong and you’ll struggle to achieve these objectives. Don’t worry though – in this post, we’ll look at how to structure your literature review for maximum impact (and marks!).

But wait – is this the right time?

Deciding on the structure of your literature review should come towards the end of the literature review process – after you have collected and digested the literature, but before you start writing the chapter. 

In other words, you need to first develop a rich understanding of the literature before you even attempt to map out a structure. There’s no use trying to develop a structure before you’ve fully wrapped your head around the existing research.

Equally importantly, you need to have a structure in place before you start writing , or your literature review will most likely end up a rambling, disjointed mess. 

Importantly, don’t feel that once you’ve defined a structure you can’t iterate on it. It’s perfectly natural to adjust as you engage in the writing process. As we’ve discussed before , writing is a way of developing your thinking, so it’s quite common for your thinking to change – and therefore, for your chapter structure to change – as you write. 

Need a helping hand?

Like any other chapter in your thesis or dissertation, your literature review needs to have a clear, logical structure. At a minimum, it should have three essential components – an  introduction , a  body   and a  conclusion . 

Let’s take a closer look at each of these.

1: The Introduction Section

Just like any good introduction, the introduction section of your literature review should introduce the purpose and layout (organisation) of the chapter. In other words, your introduction needs to give the reader a taste of what’s to come, and how you’re going to lay that out. Essentially, you should provide the reader with a high-level roadmap of your chapter to give them a taste of the journey that lies ahead.

Here’s an example of the layout visualised in a literature review introduction:

Your introduction should also outline your topic (including any tricky terminology or jargon) and provide an explanation of the scope of your literature review – in other words, what you  will   and  won’t   be covering (the delimitations ). This helps ringfence your review and achieve a clear focus . The clearer and narrower your focus, the deeper you can dive into the topic (which is typically where the magic lies). 

Depending on the nature of your project, you could also present your stance or point of view at this stage. In other words, after grappling with the literature you’ll have an opinion about what the trends and concerns are in the field as well as what’s lacking. The introduction section can then present these ideas so that it is clear to examiners that you’re aware of how your research connects with existing knowledge .

2: The Body Section

The body of your literature review is the centre of your work. This is where you’ll present, analyse, evaluate and synthesise the existing research. In other words, this is where you’re going to earn (or lose) the most marks. Therefore, it’s important to carefully think about how you will organise your discussion to present it in a clear way. 

The body of your literature review should do just as the description of this chapter suggests. It should “review” the literature – in other words, identify, analyse, and synthesise it. So, when thinking about structuring your literature review, you need to think about which structural approach will provide the best “review” for your specific type of research and objectives (we’ll get to this shortly).

There are (broadly speaking)  three options  for organising your literature review.

Option 1: Chronological (according to date)

Organising the literature chronologically is one of the simplest ways to structure your literature review. You start with what was published first and work your way through the literature until you reach the work published most recently. Pretty straightforward.

The benefit of this option is that it makes it easy to discuss the developments and debates in the field as they emerged over time. Organising your literature chronologically also allows you to highlight how specific articles or pieces of work might have changed the course of the field – in other words, which research has had the most impact . Therefore, this approach is very useful when your research is aimed at understanding how the topic has unfolded over time and is often used by scholars in the field of history. That said, this approach can be utilised by anyone that wants to explore change over time .

For example , if a student of politics is investigating how the understanding of democracy has evolved over time, they could use the chronological approach to provide a narrative that demonstrates how this understanding has changed through the ages.

Here are some questions you can ask yourself to help you structure your literature review chronologically.

• What is the earliest literature published relating to this topic?
• How has the field changed over time? Why?
• What are the most recent discoveries/theories?

In some ways, chronology plays a part whichever way you decide to structure your literature review, because you will always, to a certain extent, be analysing how the literature has developed. However, with the chronological approach, the emphasis is very firmly on how the discussion has evolved over time , as opposed to how all the literature links together (which we’ll discuss next ).

Option 2: Thematic (grouped by theme)

The thematic approach to structuring a literature review means organising your literature by theme or category – for example, by independent variables (i.e. factors that have an impact on a specific outcome).

As you’ve been collecting and synthesising literature , you’ll likely have started seeing some themes or patterns emerging. You can then use these themes or patterns as a structure for your body discussion. The thematic approach is the most common approach and is useful for structuring literature reviews in most fields.

For example, if you were researching which factors contributed towards people trusting an organisation, you might find themes such as consumers’ perceptions of an organisation’s competence, benevolence and integrity. Structuring your literature review thematically would mean structuring your literature review’s body section to discuss each of these themes, one section at a time.

Here are some questions to ask yourself when structuring your literature review by themes:

• Are there any patterns that have come to light in the literature?
• What are the central themes and categories used by the researchers?
• Do I have enough evidence of these themes?

PS – you can see an example of a thematically structured literature review in our literature review sample walkthrough video here.

Option 3: Methodological

The methodological option is a way of structuring your literature review by the research methodologies used . In other words, organising your discussion based on the angle from which each piece of research was approached – for example, qualitative , quantitative or mixed  methodologies.

Structuring your literature review by methodology can be useful if you are drawing research from a variety of disciplines and are critiquing different methodologies. The point of this approach is to question  how  existing research has been conducted, as opposed to  what  the conclusions and/or findings the research were.

For example, a sociologist might centre their research around critiquing specific fieldwork practices. Their literature review will then be a summary of the fieldwork methodologies used by different studies.

Here are some questions you can ask yourself when structuring your literature review according to methodology:

• Which methodologies have been utilised in this field?
• Which methodology is the most popular (and why)?
• What are the strengths and weaknesses of the various methodologies?
• How can the existing methodologies inform my own methodology?

3: The Conclusion Section

Once you’ve completed the body section of your literature review using one of the structural approaches we discussed above, you’ll need to “wrap up” your literature review and pull all the pieces together to set the direction for the rest of your dissertation or thesis.

The conclusion is where you’ll present the key findings of your literature review. In this section, you should emphasise the research that is especially important to your research questions and highlight the gaps that exist in the literature. Based on this, you need to make it clear what you will add to the literature – in other words, justify your own research by showing how it will help fill one or more of the gaps you just identified.

Last but not least, if it’s your intention to develop a conceptual framework for your dissertation or thesis, the conclusion section is a good place to present this.

Example: Thematically Structured Review

In the video below, we unpack a literature review chapter so that you can see an example of a thematically structure review in practice.

Let’s Recap

In this article, we’ve  discussed how to structure your literature review for maximum impact. Here’s a quick recap of what  you need to keep in mind when deciding on your literature review structure:

• Just like other chapters, your literature review needs a clear introduction , body and conclusion .
• The introduction section should provide an overview of what you will discuss in your literature review.
• The body section of your literature review can be organised by chronology , theme or methodology . The right structural approach depends on what you’re trying to achieve with your research.
• The conclusion section should draw together the key findings of your literature review and link them to your research questions.

If you’re ready to get started, be sure to download our free literature review template to fast-track your chapter outline.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

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27 Comments

Great work. This is exactly what I was looking for and helps a lot together with your previous post on literature review. One last thing is missing: a link to a great literature chapter of an journal article (maybe with comments of the different sections in this review chapter). Do you know any great literature review chapters?

I agree with you Marin… A great piece

I agree with Marin. This would be quite helpful if you annotate a nicely structured literature from previously published research articles.

Awesome article for my research.

I thank you immensely for this wonderful guide

It is indeed thought and supportive work for the futurist researcher and students

Very educative and good time to get guide. Thank you

Great work, very insightful. Thank you.

Thanks for this wonderful presentation. My question is that do I put all the variables into a single conceptual framework or each hypothesis will have it own conceptual framework?

Thank you very much, very helpful

This is very educative and precise . Thank you very much for dropping this kind of write up .

Pheeww, so damn helpful, thank you for this informative piece.

I’m doing a research project topic ; stool analysis for parasitic worm (enteric) worm, how do I structure it, thanks.

comprehensive explanation. Help us by pasting the URL of some good “literature review” for better understanding.

great piece. thanks for the awesome explanation. it is really worth sharing. I have a little question, if anyone can help me out, which of the options in the body of literature can be best fit if you are writing an architectural thesis that deals with design?

I am doing a research on nanofluids how can l structure it?

Beautifully clear.nThank you!

Lucid! Thankyou!

Brilliant work, well understood, many thanks

I like how this was so clear with simple language 😊😊 thank you so much 😊 for these information 😊

Insightful. I was struggling to come up with a sensible literature review but this has been really helpful. Thank you!

You have given thought-provoking information about the review of the literature.

Thank you. It has made my own research better and to impart your work to students I teach

I learnt a lot from this teaching. It’s a great piece.

I am doing research on EFL teacher motivation for his/her job. How Can I structure it? Is there any detailed template, additional to this?

You are so cool! I do not think I’ve read through something like this before. So nice to find somebody with some genuine thoughts on this issue. Seriously.. thank you for starting this up. This site is one thing that is required on the internet, someone with a little originality!

I’m asked to do conceptual, theoretical and empirical literature, and i just don’t know how to structure it

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APA Format for Students & Researchers

In this guide, students and researchers can learn the basics of creating a properly formatted research paper according to APA guidelines.

It includes information on how to conceptualize, outline, and format the basic structure of your paper, as well as practical tips on spelling, abbreviation, punctuation, and more. The guide concludes with a complete sample paper as well as a final checklist that writers can use to prepare their work for submission.

APA Paper Formatting Basics

• All text should be double-spaced
• Use one-inch margins on all sides
• All paragraphs in the body are indented
• Make sure that the title is centered on the page with your name and school/institution underneath
• Use 12-point font throughout
• All pages should be numbered in the upper right hand corner
• The manual recommends using one space after most punctuation marks
• A shortened version of the title (“running head”) should be placed in the upper left hand corner

Table of Contents

Here’s a quick rundown of the contents of this guide on how to do APA format.

Information related to writing and organizing your paper:

• Paper and essay categories

General paper length

• Margin sizes
• Title pages
• Running Heads
• APA Outline
• APA Abstract
• The body of papers
• APA headings and subheadings
• Use of graphics (tables and figures)

Writing style tips:

Proper tone.

• Reducing bias and labels
• Abbreviation do’s and don’ts
• Punctuation
• Number rules

Citing Your Sources:

• Citing Sources
• In-text Citations
• Reference Page

Proofing Your Paper:

• Final checklist
• Submitting your project

APA Information:

• What is APA
• APA 7 Updates

What you won’t find in this guide: This guide provides information related to the formatting of your paper, as in guidelines related to spacing, margins, word choice, etc. While it provides a general overview of APA references, it does not provide instructions for how to cite in APA format.

For step-by-step instructions for citing books, journals, how to cite a website in APA format, information on an APA format bibliography, and more, refer to these other EasyBib guides:

• APA citation (general reference guide)
• APA In-text citation
• APA article citation
• APA book citation
• APA citation website

Or, you can use our automatic generator. Our APA formatter helps to build your references for you. Yep, you read that correctly.

Writing and Organizing Your APA Paper in an Effective Way

This section of our guide focuses on proper paper length, how to format headings, spacing, and more! This information can be found in Chapter 2 of the official manual (American Psychological Association, 2020, pp. 29-67).

Categories of papers

Before getting into the nitty-gritty details related to APA research paper format, first determine the type of paper you’re about to embark on creating:

Empirical studies

Empirical studies take data from observations and experiments to generate research reports. It is different from other types of studies in that it isn’t based on theories or ideas, but on actual data.

Literature reviews

These papers analyze another individual’s work or a group of works. The purpose is to gather information about a current issue or problem and to communicate where we are today. It sheds light on issues and attempts to fill those gaps with suggestions for future research and methods.

Theoretical articles

These papers are somewhat similar to a literature reviews in that the author collects, examines, and shares information about a current issue or problem, by using others’ research. It is different from literature reviews in that it attempts to explain or solve a problem by coming up with a new theory. This theory is justified with valid evidence.

Methodological articles

These articles showcase new advances, or modifications to an existing practice, in a scientific method or procedure. The author has data or documentation to prove that their new method, or improvement to a method, is valid. Plenty of evidence is included in this type of article. In addition, the author explains the current method being used in addition to their own findings, in order to allow the reader to understand and modify their own current practices.

Case studies

Case studies present information related an individual, group, or larger set of individuals. These subjects are analyzed for a specific reason and the author reports on the method and conclusions from their study. The author may also make suggestions for future research, create possible theories, and/or determine a solution to a problem.

Since APA style format is used often in science fields, the belief is “less is more.” Make sure you’re able to get your points across in a clear and brief way. Be direct, clear, and professional. Try not to add fluff and unnecessary details into your paper or writing.  This will keep the paper length shorter and more concise.

Margin sizes in APA Format

When it comes to margins, keep them consistent across the left, right, top, and bottom of the page. All four sides should be the same distance from the edge of the paper. It’s recommended to use at least one-inch margins around each side. It’s acceptable to use larger margins, but the margins should never be smaller than an inch.

Title pages in APA Format

The title page, or APA format cover page, is the first page of a paper or essay. Some teachers and professors do not require a title page, but some do. If you’re not sure if you should include one or not, ask your teacher. Some appreciate the page, which clearly displays the writer’s name and the title of the paper.

The APA format title page for student papers includes six main components:

• the title of the APA format paper
• names of all authors
• institutional affiliation
• course number and title
• instructor’s name

Title pages for professional papers  also require a running head; student papers do not.

Some instructors and professional publications also ask for an author’s note. If you’re required or would like to include an author’s note, place it below the institutional affiliation. Examples of information included in an author’s note include an ORCID iD number, a disclosure, and an acknowledgement.

Here are key guidelines to developing your title page:

• The title of the paper should capture the main idea of the essay, but should not contain abbreviations or words that serve no purpose. For example, instead of using the title “A Look at Amphibians From the Past,” title the paper “Amphibians From the Past.” Delete the unnecessary fluff!
• Center the title on the page and place it about 3-4 lines from the top.
• The title should be bolded, in title case, and the same font size as your other page text. Do not underline or italicize the title. Other text on the page should be plain (not bolded , underlined, or italicized ). 
• All text on the title page should be double-spaced. The APA format examples paper below displays proper spacing, so go take a look!
• Do not include any titles in the author’s name such as Dr. or Ms. In contrast, for your instructor’s name, use the form they prefer (e.g., Sagar Parekh, PhD; Dr. Minako Asato; Professor Nathan Ian Brown; etc.).
• The institutional affiliation is the school the author attends or the location where the author conducted the research.

In a hurry? Try the  EasyBib title page maker to easily create a title page for free.

Sample of an APA format title page for a student paper:

Sample of title page for a professional paper:

Running heads in APA Format

The 7th edition of the American Psychological Association Publication Manual (p. 37) states that running heads are not required for student papers unless requested by the instructor. Student papers still need a page number included in the upper right-hand corner of every page. The 6th edition required a running head for student papers, so be sure to confirm with your instructor which edition you should follow. Of note, this guide follows the 7th edition.

Running heads are required for professional papers (e.g., manuscripts submitted for publication). Read on for instructions on how to create them.

Are you wondering what is a “running head”? It’s basically a page header at the top of every page. To make this process easier, set your word processor to automatically add these components onto each page. You may want to look for “Header” in the features.

A running head/page header includes two pieces:

• the title of the paper
• page numbers.

Insert page numbers justified to the right-hand side of the APA format paper (do not put p. or pg. in front of the page numbers).

For all pages of the paper, including the APA format title page, include the “TITLE OF YOUR PAPER” justified to the left in capital letters (i.e., the running head). If your full title is long (over 50 characters), the running head title should be a shortened version.

Preparing outlines in APA Format

Outlines are extremely beneficial as they help writers stay organized, determine the scope of the research that needs to be included, and establish headings and subheadings.

There isn’t an official or recommended “APA format for outline” structure. It is up to the writer (if they choose to make use of an outline) to determine how to organize it and the characters to include. Some writers use a mix of roman numerals, numbers, and uppercase and lowercase letters.

Even though there isn’t a required or recommended APA format for an outline, we encourage writers to make use of one. Who wouldn’t want to put together a rough outline of their project? We promise you, an outline will help you stay on track.

Here’s our version of how APA format for outlines could look:

Don’t forget, if you’re looking for information on APA citation format and other related topics, check out our other comprehensive guides.

How to form an abstract in APA

An APA format abstract (p. 38) is a summary of a scholarly article or scientific study. Scholarly articles and studies are rather lengthy documents, and abstracts allow readers to first determine if they’d like to read an article in its entirety or not.

You may come across abstracts while researching a topic. Many databases display abstracts in the search results and often display them before showing the full text of an article or scientific study. It is important to create a high quality abstract that accurately communicates the purpose and goal of your paper, as readers will determine if it is worthy to continue reading or not.

Are you wondering if you need to create an abstract for your assignment? Usually, student papers do not require an abstract. Abstracts are not typically seen in class assignments, and are usually only included when submitting a paper for publication. Unless your teacher or professor asked for it, you probably don’t need to have one for your class assignment.

If you’re planning on submitting your paper to a journal for publication, first check the journal’s website to learn about abstract and APA paper format requirements.

Here are some helpful suggestions to create a dynamic abstract:

• Abstracts are found on their own page, directly after the title or cover page.
• Professional papers only (not student papers): Include the running head on the top of the page.
• On the first line of the page, center the word “Abstract” (but do not include quotation marks).
• On the following line, write a summary of the key points of your research. Your abstract summary is a way to introduce readers to your research topic, the questions that will be answered, the process you took, and any findings or conclusions you drew. Use concise, brief, informative language. You only have a few sentences to share the summary of your entire document, so be direct with your wording.
• This summary should not be indented, but should be double-spaced and less than 250 words.
• If applicable, help researchers find your work in databases by listing keywords from your paper after your summary. To do this, indent and type Keywords : in italics.  Then list your keywords that stand out in your research. You can also include keyword strings that you think readers will type into the search box.
• Active voice: The subjects reacted to the medication.
• Passive voice: There was a reaction from the subjects taking the medication.
• Instead of evaluating your project in the abstract, simply report what it contains.
• If a large portion of your work includes the extension of someone else’s research, share this in the abstract and include the author’s last name and the year their work was released.

APA format example page:

Here’s an example of an abstract:

Visual design is a critical aspect of any web page or user interface, and its impact on a user’s experience has been studied extensively. Research has shown a positive correlation between a user’s perceived usability and a user’s assessment of visual design. Additionally, perceived web quality, which encompasses visual design, has a positive relationship with both initial and continued consumer purchase intention. However, visual design is often assessed using self-report scale, which are vulnerable to a few pitfalls. Because self-report questionnaires are often reliant on introspection and honesty, it is difficult to confidently rely on self-report questionnaires to make important decisions. This study aims to ensure the validity of a visual design assessment instrument (Visual Aesthetics of Websites Inventory: Short version) by examining its relationship with biometric (variables), like galvanic skin response, pupillometry, and fixation information. Our study looked at participants assessment of a webpage’s visual design, and compared it to their biometric responses while viewing the webpage. Overall, we found that both average fixation duration and pupil dilation differed when participants viewed web pages with lower visual design ratings compared to web pages with a higher visual design rating.

Keywords : usability, visual design, websites, eye tracking, pupillometry, self-report, VisAWI

The body of an APA paper

On the page after the title page (if a student paper) or the abstract (if a professional paper), begin with the body of the paper.

Most papers follow this format:

• At the top of the page, add the page number in the upper right corner of all pages, including the title page.
• On the next line write the title in bold font and center it. Do not underline or italicize it.
• Begin with the introduction and indent the first line of the paragraph. All paragraphs in the body are indented.

Sample body for a student paper:

Most scientific or professional papers have additional sections and guidelines:

• Start with the running head (title + page number). The heading title should be in capital letters. The abstract page should be page 2.
• The introduction presents the problem and premise upon which the research was based. It goes into more detail about this problem than the abstract.
• Begin a new section with the Method and use this word as the subtitle. Bold and center this subtitle. The Method section shows how the study was run and conducted. Be sure to describe the methods through which data was collected.
• Begin a new section with the Results . Bold and center this subtitle. The Results section summarizes your data. Use charts and graphs to display this data.
• Draw conclusions and support how your data led to these conclusions.
• Discuss whether or not your hypothesis was confirmed or not supported by your results.
• Determine the limitations of the study and next steps to improve research for future studies.

Sample body for a professional paper:

Keep in mind, APA citation format is much easier than you think, thanks to EasyBib.com. Try our automatic generator and watch how we create APA citation format references for you in just a few clicks. While you’re at it, take a peek at our other helpful guides, such as our APA reference page guide, to make sure you’re on track with your research papers.

Proper usage of headings & subheadings in APA Format

Headings (p. 47) serve an important purpose in research papers — they organize your paper and make it simple to locate different pieces of information. In addition, headings provide readers with a glimpse to the main idea, or content, they are about to read.

In APA format, there are five levels of headings, each with a different formatting:

• This is the title of your paper
• The title should be centered in the middle of the page
• The title should be bolded
• Use uppercase and lowercase letters where necessary (called title capitalization)
• Place this heading against the left margin
• Use bold letters
• Use uppercase and lowercase letters where necessary
• Place this heading against the left side margin
• End the heading with a period
• Indented in from the left margin

Following general formatting rules, all headings are double spaced and there are no extra lines or spaces between sections.

Here is a visual APA format template for levels of headings:

Use of graphics (tables and figures) in APA Format

If you’re looking to jazz up your project with any charts, tables, drawings, or images, there are certain APA format rules (pp. 195-250) to follow.

First and foremost, the only reason why any graphics should be added is to provide the reader with an easier way to see or read information, rather than typing it all out in the text.

Lots of numbers to discuss? Try organizing your information into a chart or table. Pie charts, bar graphs, coordinate planes, and line graphs are just a few ways to show numerical data, relationships between numbers, and many other types of information.

Instead of typing out long, drawn out descriptions, create a drawing or image. Many visual learners would appreciate the ability to look at an image to make sense of information.

Before you go ahead and place that graphic in your paper, here are a few key guidelines:

• Follow them in the appropriate numerical order in which they appear in the text of your paper. Example : Figure 1, Figure 2, Table 1, Figure 3.
• Example: Figure 1, Figure 2, Table 1, Figure 3
• Only use graphics if they will supplement the material in your text. If they reinstate what you already have in your text, then it is not necessary to include a graphic.
• Include enough wording in the graphic so that the reader is able to understand its meaning, even if it is isolated from the corresponding text. However, do not go overboard with adding a ton of wording in your graphic.
• Left align tables and figures

In our APA format sample paper , you’ll find examples of tables after the references. You may also place tables and figures within the text just after it is mentioned.

Is there anything better than seeing a neatly organized data table? We think not! If you have tons of numbers or data to share, consider creating a table instead of typing out a wordy paragraph. Tables are pretty easy to whip up on Google Docs or Microsoft Word.

General format of a table should be:

• Table number
• Choose to type out your data OR create a table. As stated above, in APA format, you shouldn’t have the information typed out in your paper and also have a table showing the same exact information. Choose one or the other.
• If you choose to create a table, discuss it very briefly in the text. Say something along the lines of, “Table 1 displays the amount of money used towards fighting Malaria.” Or, “Stomach cancer rates are displayed in Table 4.”
• If you’re submitting your project for a class, place your table close to the text where it’s mentioned. If you’re submitting it to be published in a journal, most publishers prefer tables to be placed in the back. If you’re unsure where to place your tables, ask!
• Include the table number first and at the top. Table 1 is the first table discussed in the paper. Table 2 is the next table mentioned, and so on. This should be in bold.
• Add a title under the number. Create a brief, descriptive title. Capitalize the first letter for each important word. Italicize the title and place it under the table number.
• Only use horizontal lines.
• Limit use of cell shading.
• Keep the font at 12-point size and use single or double spacing. If you use single spacing in one table, make sure all of the others use single spaces as well. Keep it consistent.
• All headings should be centered.
• In the first column (called the stub), center the heading, left-align the information underneath it (indent 0.15 inches if info is more than one line).
• Information in other columns should be centered.
• General . Information about the whole table.
• Specific . Information targeted for a specific column, row, or cell.
• Probability . Explains what certain table symbols mean. For example, asterisks,  p values, etc.

Here’s an APA format example of a table:

We know putting together a table is pretty tricky. That’s why we’ve included not one, but a few tables on this page. Scroll down and look at the additional tables in the essay in APA format example found below.

Figures represent information in a visual way. They differ from tables in that they are visually appealing. Sure, tables, like the one above, can be visually appealing, but it’s the color, circles, arrows, boxes, or icons included that make a figure a “figure.”

There are many commonly used figures in papers. Examples APA Format:

• Photographs
• Hierarchy charts

General format of a figure is the same as tables. This means each should include:

• Figure number

Use the same formatting tables use for the number, title, and note.

Here are some pointers to keep in mind when it comes to APA format for figures:

• Only include a figure if it adds value to your paper. If it will truly help with understanding, include it!
• Either include a figure OR write it all out in the text. Do not include the same information twice.
• If a note is added, it should clearly explain the content of the figure. Include any reference information if it’s reproduced or adapted.

APA format sample of a figure:

Photographs:

We live in a world where we have tons of photographs available at our fingertips.

Photographs found through Google Images, social media, stock photos made available from subscription sites, and tons of other various online sources make obtaining photographs a breeze. We can even pull out our cell phones, and in just a few seconds, take pictures with our cameras.

Photographs are simple to find, and because of this, many students enjoy using them in their papers.

If you have a photograph you would like to include in your project, here are some guidelines from the American Psychological Association.

• Create a reference for the photograph. Follow the guidelines under the table and figure sections above.
• Do not use color photos. It is recommended to use black and white. Colors can change depending on the reader’s screen resolution. Using black and white ensures the reader will be able to view the image clearly. The only time it is recommended to use color photos is if you’re writing about color-specific things. For example, if you’re discussing the various shades of leaf coloration, you may want to include a few photographs of colorful leaves.
• If there are sections of the photograph that are not related to your work, it is acceptable to crop them out. Cropping is also beneficial in that it helps the reader focus on the main item you’re discussing.
• If you choose to include an image of a person you know, it would be respectful if you ask their permission before automatically including their photo in your paper.  Some schools and universities post research papers online and some people prefer that their photos and information stay off the Internet.

B. Writing Style Tips

Writing a paper for scientific topics is much different than writing for English, literature, and other composition classes. Science papers are much more direct, clear, and concise. This section includes key suggestions, explains how to write in APA format, and includes other tidbits to keep in mind while formulating your research paper.

Verb usage in APA

Research experiments and observations rely on the creation and analysis of data to test hypotheses and come to conclusions. While sharing and explaining the methods and results of studies, science writers often use verbs.

When using verbs in writing, make sure that you continue to use them in the same tense throughout the section you’re writing. Further details are in the publication manual (p. 117).

Here’s an APA format example:

We tested the solution to identify the possible contaminants.

It wouldn’t make sense to add this sentence after the one above:

We tested the solution to identify the possible contaminants. Researchers often test solutions by placing them under a microscope.

Notice that the first sentence is in the past tense while the second sentence is in the present tense. This can be confusing for readers.

For verbs in scientific papers, the APA manual recommends using:

• Past tense or present perfect tense for the explantation of the procedure
• Past tense for the explanation of the results
• Present tense for the explanation of the conclusion and future implications

If this is all a bit much, and you’re simply looking for help with your references, try the EasyBib.com APA format generator . Our APA formatter creates your references in just a few clicks. APA citation format is easier than you think thanks to our innovative, automatic tool.

Even though your writing will not have the same fluff and detail as other forms of writing, it should not be boring or dull to read. The Publication Manual suggests thinking about who will be the main reader of your work and to write in a way that educates them.

How to reduce bias & labels

The American Psychological Association strongly objects to any bias towards gender, racial groups, ages of individuals or subjects, disabilities, and sexual orientation (pp. 131-149). If you’re unsure whether your writing is free of bias and labels or not, have a few individuals read your work to determine if it’s acceptable.

Here are a few guidelines that the American Psychological Association suggests :

• Only include information about an individual’s orientation or characteristic if it is important to the topic or study. Do not include information about individuals or labels if it is not necessary.
• If writing about an individual’s characteristic or orientation, for essay APA format, make sure to put the person first. Instead of saying, “Diabetic patients,” say, “Patients who are diabetic.”
• Instead of using narrow terms such as, “adolescents,” or “the elderly,” try to use broader terms such as, “participants,” and “subjects.”
• “They” or “their” are acceptable gender-neutral pronouns to use.
• Be mindful when using terms that end with “man” or “men” if they involve subjects who are female. For example, instead of using “Firemen,” use the term, “Firefighter.” In general, avoid ambiguity.
• When referring to someone’s racial or ethnic identity, use the census category terms and capitalize the first letter. Also, avoid using the word, “minority,” as it can be interpreted as meaning less than or deficient. Instead, say “people of color” or “underrepresented groups.”
• When describing subjects in APA format, use the words “girls” and “boys” for children who are under the age of 12. The terms, “young woman,” “young man,” “female adolescent,” and “male adolescent” are appropriate for subjects between 13-17 years old; “Men,” and “women,” for those older than 18. Use the term, “older adults.” for individuals who are older. “Elderly,” and “senior,” are not acceptable if used only as nouns. It is acceptable to use these terms if they’re used as adjectives.

Read through our example essay in APA format, found in section D, to see how we’ve reduced bias and labels.

Spelling in APA Format

• In APA formatting, use the same spelling as words found in Merriam-Webster’s Collegiate Dictionary (American English) (p. 161).
• If the word you’re trying to spell is not found in Webster’s Collegiate Dictionary, a second resource is Webster’s Third New International Dictionary .
• If attempting to properly spell words in the psychology field, consult the American Psychological Association’s Dictionary of Psychology

Thanks to helpful tools and features, such as the spell checker, in word processing programs, most of us think we have everything we need right in our document. However, quite a few helpful features are found elsewhere.

Where can you find a full grammar editor? Right here, on EasyBib.com. The EasyBib Plus paper checker scans your paper for spelling, but also for any conjunction , determiner, or adverb out of place. Try it out and unlock the magic of an edited paper.

Abbreviation do’s and don’ts in APA Format

Abbreviations can be tricky. You may be asking yourself, “Do I include periods between the letters?” “Are all letters capitalized?” “Do I need to write out the full name each and every time?” Not to worry, we’re breaking down the publication manual’s abbreviations (p. 172) for you here.

First and foremost, use abbreviations sparingly.

Too many and you’re left with a paper littered with capital letters mashed together. Plus, they don’t lend themselves to smooth and easy reading. Readers need to pause and comprehend the meaning of abbreviations and quite often stumble over them.

• If the abbreviation is used less than three times in the paper, type it out each time. It would be pretty difficult to remember what an abbreviation or acronym stands for if you’re writing a lengthy paper.
• If you decide to sprinkle in abbreviations,  it is not necessary to include periods between the letters.
• Example: While it may not affect a patient’s short-term memory (STM), it may affect their ability to comprehend new terms. Patients who experience STM loss while using the medication should discuss it with their doctor.
• Example : AIDS
• The weight in pounds exceeded what we previously thought.

Punctuation in APA Format

One space after most punctuation marks.

The manual recommends using one space after most punctuation marks, including punctuation at the end of a sentence (p. 154). It doesn’t hurt to double check with your teacher or professor to ask their preference since this rule was changed recently (in 2020).

The official APA format book was primarily created to aid individuals with submitting their paper for publication in a professional journal. Many schools adopt certain parts of the handbook and modify sections to match their preference. To see an example of an APA format research paper, with the spacing we believe is most commonly and acceptable to use, scroll down and see section D.

For more information related to the handbook, including frequently asked questions, and more, here’s further reading on the style

It’s often a heated debate among writers whether or not to use an Oxford comma (p. 155), but for this style, always use an Oxford comma. This type of comma is placed before the words AND and OR or in a series of three items.

Example of APA format for commas: The medication caused drowsiness, upset stomach, and fatigue.

Here’s another example: The subjects chose between cold, room temperature, or warm water.

Apostrophes

When writing a possessive singular noun, you should place the apostrophe before the s. For possessive plural nouns, the apostrophe is placed after the s.

• Singular : Linda Morris’s jacket
• Plural : The Morris’ house

Em dashes (long dash) are used to bring focus to a particular point or an aside. There are no spaces after these dashes (p. 157).

Use en dashes (short dash) in compound adjectives. Do not place a space before or after the dash. Here are a few examples:

• custom-built
• 12-year-old

Number rules in APA Format

Science papers often include the use of numbers, usually displayed in data, tables, and experiment information. The golden rule to keep in mind is that numbers less than 10 are written out in text. If the number is more than 10, use numerals.

APA format examples:

• 14 kilograms
• seven individuals
• 83 years old
• Fourth grade

The golden rule for numbers has exceptions.

In APA formatting, use numerals if you are:

• Showing numbers in a table or graph
• 4 divided by 2
• 6-month-olds

Use numbers written out as words if you are:

• Ninety-two percent of teachers feel as though….
• Hundred Years’ War
• One-sixth of the students

Other APA formatting number rules to keep in mind:

• World War II
• Super Bowl LII
• It’s 1980s, not 1980’s!

Additional number rules can be found in the publication manual (p. 178)

Need help with other writing topics? Our plagiarism checker is a great resource for anyone looking for writing help. Say goodbye to an out of place noun , preposition , or adjective, and hello to a fully edited paper.

Overview of APA references

While writing a research paper, it is always important to give credit and cite your sources; this lets you acknowledge others’ ideas and research you’ve used in your own work. Not doing so can be considered plagiarism , possibly leading to a failed grade or loss of a job.

APA style is one of the most commonly used citation styles used to prevent plagiarism. Here’s more on crediting sources . Let’s get this statement out of the way before you become confused: An APA format reference and an APA format citation are two different things! We understand that many teachers and professors use the terms as if they’re synonyms, but according to this specific style, they are two separate things, with different purposes, and styled differently.

A reference displays all of the information about the source — the title, the author’s name, the year it was published, the URL, all of it! References are placed on the final page of a research project.

Here’s an example of a reference:

Wynne-Jones, T. (2015). The emperor of any place . Candlewick Press.

An APA format citation is an APA format in-text citation. These are found within your paper, anytime a quote or paraphrase is included. They usually only include the name of the author and the date the source was published.

Here’s an example of one:

Hypertrophic cardiomyopathy is even discussed in the book, The Emperor of Any Place . The main character, Evan, finds a mysterious diary on his father’s desk (the same desk his father died on, after suffering from a hypertrophic cardiomyopathy attack). Evan unlocks the truth to his father and grandfather’s past (Wynne-Jones, 2015).

Both of the ways to credit another individual’s work — in the text of a paper and also on the final page — are key to preventing plagiarism. A writer must use both types in a paper. If you cite something in the text, it must have a full reference on the final page of the project. Where there is one, there must be the other!

Now that you understand that, here’s some basic info regarding APA format references (pp. 281-309).

• Each reference is organized, or structured, differently. It all depends on the source type. A book reference is structured one way, an APA journal is structured a different way, a newspaper article is another way. Yes, it’s probably frustrating that not all references are created equal and set up the same way. MLA works cited pages are unique in that every source type is formatted the same way. Unfortunately, this style is quite different.
• Most references follow this general format:

Author’s Last name, First initial. Middle initial. (Year published). Title of source . URL.

Again, as stated in the above paragraph, you must look up the specific source type you’re using to find out the placement of the title, author’s name, year published, etc.

For more information on APA format for sources and how to reference specific types of sources, use the other guides on EasyBib.com. Here’s another useful site .

Looking for a full visual of a page of references? Scroll down and take a peek at our APA format essay example towards the bottom of this page. You’ll see a list of references and you can gain a sense of how they look.

Bonus: here’s a link to more about the fundamentals related to this particular style. If you want to brush up or catch up on the Modern Language Association’s style, here’s a great resource on how to cite websites in MLA .

In-text APA citation format

Did you find the perfect quote or piece of information to include in your project? Way to go! It’s always a nice feeling when we find that magical piece of data or info to include in our writing. You probably already know that you can’t just copy and paste it into your project, or type it in, without also providing credit to the original author.

Displaying where the original information came from is much easier than you think.Directly next to the quote or information you included, place the author’s name and the year nearby. This allows the reader of your work to see where the information originated.

APA allows for the use of two different forms of in-text citation, parenthetical and narrative Both forms of citation require two elements:

• author’s name
• year of publication

The only difference is the way that this information is presented to the reader.

Parenthetical citations are the more commonly seen form of in-text citations for academic work, in which both required reference elements are presented at the end of the sentence in parentheses. Example:

Harlem had many artists and musicians in the late 1920s (Belafonte, 2008).

Narrative citations allow the author to present one or both of the required reference elements inside of the running sentence, which prevents the text from being too repetitive or burdensome. When only one of the two reference elements is included in the sentence, the other is provided parenthetically. Example:

According to Belafonte (2008), Harlem was full of artists and musicians in the late 1920s.

If there are two authors listed in the source entry, then the parenthetical reference must list them both:

(Smith & Belafonte, 2008)

If there are three or more authors listed in the source entry, then the parenthetical reference can abbreviate with “et al.”, the latin abbreviation for “and others”:

(Smith et al., 2008)

The author’s names are structured differently if there is more than one author. Things will also look different if there isn’t an author at all (which is sometimes the case with website pages). For more information on APA citation format, check out this page on the topic: APA parenthetical citation and APA in-text citation . There is also more information in the official manual in chapter 8.

If it’s MLA in-text and parenthetical citations you’re looking for, we’ve got your covered there too! You might want to also check out his guide on parenthetical citing .

Would you benefit from having a tool that helps you easily generate citations that are in the text? Check out EasyBib Plus!

References page in APA Format

An APA format reference page is easier to create than you probably think. We go into detail on how to create this page on our APA reference page . We also have a guide for how to create an annotated bibliography in APA . But, if you’re simply looking for a brief overview of the reference page, we’ve got you covered here.

Here are some pointers to keep in mind when it comes to the references page in APA format:

• This VIP page has its very own page. Start on a fresh, clean document (p. 303).
• Center and bold the title “References” (do not include quotation marks, underline, or italicize this title).
• Alphabetize and double-space ALL entries.
• Use a readable font, such as Times New Roman, Arial, Calibri, or Lucida (p. 44).
• Every quote or piece of outside information included in the paper should be referenced and have an entry.
• Even though it’s called a “reference page,” it can be longer than one page. If your references flow onto the next page, then that’s a-okay.
• Only include the running head if it is required by your teacher or you’re writing a professional paper.

Sample reference page for a student paper:

Here’s another friendly reminder to use the EasyBib APA format generator (that comes with EasyBib Plus) to quickly and easily develop every single one of your references for you. Try it out! Our APA formatter is easy to use and ready to use 24/7.

Final APA Format Checklist

Prior to submitting your paper, check to make sure you have everything you need and everything in its place:

• Did you credit all of the information and quotes you used in the body of your paper and show a matching full reference at the end of the paper? Remember, you need both! Need more information on how to credit other authors and sources? Check out our other guides, or use the EasyBib APA format generator to credit your sources quickly and easily. EasyBib.com also has more styles than just the one this page focuses on.
• 12-pt. Times New Roman
• 11-pt. Calibri, Arial, Georgia
• 10-pt. Lucida, Sans Unicode, Computer Modern
• If you created an abstract, is it directly after the title page? Some teachers and professors do not require an abstract, so before you go ahead and include it, make sure it’s something he or she is expecting.
• Professional paper — Did you include a running head on every single page of your project?
• Student paper — Did you include page numbers in the upper right-hand corner of all your pages?
• Are all headings, as in section or chapter titles, properly formatted? If you’re not sure, check section number 9.
• Are all tables and figures aligned properly? Did you include notes and other important information directly below the table or figure? Include any information that will help the reader completely understand everything in the table or figure if it were to stand alone.
• Are abbreviations used sparingly? Did you format them properly?
• Is the entire document double spaced?
• Are all numbers formatted properly? Check section 17, which is APA writing format for numbers.
• Did you glance at the sample paper? Is your assignment structured similarly? Are all of the margins uniform?

Submitting Your APA Paper

Congratulations for making it this far! You’ve put a lot of effort into writing your paper and making sure the t’s are crossed and the i’s are dotted. If you’re planning to submit your paper for a school assignment, make sure you review your teacher or professor’s procedures.

If you’re submitting your paper to a journal, you probably need to include a cover letter.

Most cover letters ask you to include:

• The author’s contact information.
• A statement to the editor that the paper is original.
• If a similar paper exists elsewhere, notify the editor in the cover letter.

Once again, review the specific journal’s website for exact specifications for submission.

Okay, so you’re probably thinking you’re ready to hit send or print and submit your assignment. Can we offer one last suggestion? We promise it will only take a minute.

Consider running your paper through our handy dandy paper checker. It’s pretty simple.

Copy and paste or upload your paper into our checker. Within a minute, we’ll provide feedback on your spelling and grammar. If there’s a pronoun , interjection , or verb out of place, we’ll highlight it and offer suggestions for improvement. We’ll even take it a step further and point out any instances of possible plagiarism.

If it sounds too good to be true, then head on over to our innovative tool and give it a whirl. We promise you won’t be disappointed.

What is APA Format?

APA stands for the American Psychological Association . In this guide, you’ll find information related to “What is APA format?” in relation to writing and organizing your paper according to the American Psychological Association’s standards. Information on how to cite sources can be found on our APA citation page. The official American Psychological Association handbook was used as a reference for our guide and we’ve included page numbers from the manual throughout. However, this page is not associated with the association.

You’ll most likely use APA format if your paper is on a scientific topic. Many behavioral and social sciences use this organization’s standards and guidelines.

What are behavioral sciences? Behavioral sciences study human and animal behavior. They can include:

• Cognitive Science
• Neuroscience

What are social sciences? Social sciences focus on one specific aspect of human behavior, specifically social and cultural relationships. Social sciences can include:

• Anthropology
• Political Science
• Human Geography
• Archaeology
• Linguistics

What’s New in the 7th Edition?

This citation style was created by the American Psychological Association. Its rules and guidelines can be found in the Publication Manual of the American Psychological Association . The information provided in the guide above follows the 6th edition (2009) of the manual. The 7th edition was published in 2020 and is the most recent version.

The 7th edition of the Publication Manual is in full color and includes 12 sections (compared to 8 sections in the 6th edition). In general, this new edition differentiates between professional and student papers, includes guidance with accessibility in mind, provides new examples to follow, and has updated guidelines.We’ve selected a few notable updates below, but for a full view of all of the 7th edition changes visit the style’s website linked here .

• Paper title
• Student name
• Affiliation (e.g., school, department, etc.)
• Course number and title
• Course instructor
• 6th edition – Running head: SMARTPHONE EFFECTS ON ADOLESCENT SOCIALIZATION
• 7th edition – SMARTPHONE EFFECTS ON ADOLESCENT SOCIALIZATION
• Pronouns . “They” can be used as a gender-neutral pronoun.
• Bias-free language guidelines . There are updated and new sections on guidelines for this section. New sections address participation in research, socioeconomic status, and intersectionality.
• Spacing after sentences. Add only a single space after end punctuation.
• Tables and figures . The citing format is now streamlined so that both tables and figures should include a name and number above the table/figure, and a note underneath the table/figure.
• 6th ed. – (Ikemoto, Richardson, Murphy, Yoshida 2016)
• 7th ed. – (Ikemoto et al., 2016)
• Citing books. The location of the publisher can be omitted. Also, e-books no longer need to mention the format (e.g., Kindle, etc.)
• Example: https://doi.org/10.1038/s42255-019-0153-5
• Using URLs. URLs no longer need to be prefaced by the words “Retrieved from.”

New citing information . There is new guidance on citing classroom or intranet resources, and oral traditions or traditional knowledge of indigenous peoples.

Visit our EasyBib Twitter feed to discover more citing tips, fun grammar facts, and the latest product updates.

American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.) (2020). American Psychological Association. https://doi.org/10.1037/0000165-000

Published October 31, 2011. Updated May 14, 2020.

Written and edited by Michele Kirschenbaum and Elise Barbeau. Michele Kirschenbaum is a school library media specialist and the in-house librarian at EasyBib.com. Elise Barbeau is the Citation Specialist at Chegg. She has worked in digital marketing, libraries, and publishing.

APA Formatting Guide

APA Formatting

• Annotated Bibliography
• Block Quotes
• et al Usage
• Multiple Authors
• Paraphrasing
• Page Numbers
• Parenthetical Citations
• Sample Paper
• View APA Guide

Citation Examples

• Book Chapter
• Journal Article
• Magazine Article
• Newspaper Article
• Website (no author)
• View all APA Examples

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We should not use “et al.” in APA reference list entries. If the number of authors in the source is up to and including 20, list all author names and use an ampersand (&) before the final author’s name. If the number of authors is more than 20, list the first 19 authors’ names followed by an ellipsis (but no ampersand), and then add the final author’s name. An example of author names in a reference entry having more than 20 authors is given below:

Author Surname1, F. M., Author Surname2, F. M., Author Surname3, F. M., Author Surname4, F. M., Author Surname5, F. M., Author Surname6, F. M., Author Surname7, F. M., Author Surname8, F. M., Author Surname9, F. M., Author Surname10, F. M., Author Surname11, F. M., Author Surname12, F. M., Author Surname13, F. M., Author Surname14, F. M., Author Surname15, F. M., Author Surname16, F. M., Author Surname17, F. M., Author Surname18, F. M., Author Surname19, F. M., . . .  Last Author Surname, F. M. (Publication Year).

Alvarez, L. D., Peach, J. L., Rodriguez, J. F., Donald, L., Thomas, M., Aruck, A., Samy, K., Anthony, K., Ajey, M., Rodriguez, K. L., Katherine, K., Vincent, A., Pater, F., Somu, P., Pander, L., Berd, R., Fox, L., Anders, A., Kamala, W., . . . Nicole Jones, K. (2019).

Note that, unlike references with 2 to 20 author names, the symbol “&” is not used here before the last author’s name.

APA 7, released in October 2019, has some new updates. Here is a brief description of the updates made in APA 7.

Different types of papers and best practices are given in detail in Chapter 1.

How to format a student title page is explained in Chapter 2. Examples of a professional paper and a student paper are included.

Chapter 3 provides additional information on qualitative and mixed methods of research.

An update on writing style is included in Chapter 4.

In chapter 5, some best practices for writing with bias-free language are included.

Chapter 6 gives some updates on style elements including using a single space after a period, including a citation with an abbreviation, the treatment of numbers in abstracts, treatment for different types of lists, and the formatting of gene and protein names.

In Chapter 7, additional examples are given for tables and figures for different types of publications.

In Chapter 8, how to format quotations and how to paraphrase text are covered with additional examples. A simplified version of in-text citations is clearly illustrated.

Chapter 9 has many updates: listing all author names up to 20 authors, standardizing DOIs and URLs, and the formatting of an annotated bibliography.

Chapter 10 includes many examples with templates for all reference types. New rules covering the inclusion of the issue number for journals and the omission of publisher location from book references are provided. Explanations of how to cite YouTube videos, power point slides, and TED talks are included.

Chapter 11 includes many legal references for easy understanding.

Chapter 12 provides advice for authors on how to promote their papers.

For more information on some of the changes found in APA 7, check out this EasyBib article .

APA Citation Examples

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Research papers.

• Research Paper Basics
• Credible Sources
• Reading Scholarly Articles
• Summarizing and Paraphrasing
• Paraphrasing and Student Voice
• Direct Quotations
• Synthesis in Writing
• Citing Sources

How to Read an Academic Article

Sections of an academic article.

Most academic journal articles include the following sections:

• Abstract  (An executive summary of the study)
• Introduction (Definition of the research question to be studied)
• Literature Review (A summary of past research noting where gaps exist)
• Methods (The research design including variables, sample size, measurements)
• Data (Information gathered through the study often displayed in tables and charts)
• Results (Conclusions reached at the end of the study) Conclusion (Discussion of whether the study proved the thesis; may suggest opportunities for further research) Bibliography (A list of works cited in the journal article)

TIP: To begin selecting articles for your research, read the highlighted sections to determine whether the academic journal article includes information relevant to your research topic.

Step 1: Skim the Article

When sorting through multiple articles discovered in the research process, skimming through these sections of the article will help you determine whether the article will be useful in your research.

• Article title  and subject headings assigned to the article
• Introduction

If the article fits your information needs, go back and read the article thoroughly. TIP: Create a folder on your computer to save copies of articles you plan to use, and save your references.

Step 2: Determine Your Purpose

Think about how you will evaluate the academic articles you find and how you will determine whether to include them in your research project.  Ask yourself the following questions to focus your search in the academic literature: ​

• Are you looking for an overview of a topic or an explanation of a specific concept, idea, or position?
• Are you exploring gaps in the research to identify a new area for academic study?
• Are you looking for research that supports or disagrees with your thesis or research question?
• Are you looking for examples of a research design and/or research methods you are considering for your own research project?

Step 3: Read Critically

Before reading the article, ask yourself the following:

• What is my research question? What position am I trying to support?
• What do I already know about this topic?  What do I need to learn?
• How will I evaluate the article?  Author's reputation? Research design? Treatment of topic? 
• What are my biases about the topic?

As you read the article make note of the following:

• Who is the intended audience for this article?
• What is the author's purpose in writing this article?
• What is the main point?
• How was the main point proven or supported?  
• Were scientific methods used in conducting the research? Do you agree or disagree with the author? Why?
• How does this article compare or connect with other articles on the topic?
• Does the author recommend areas for further study?
• How does this article help to answer your research question?
• << Previous: Credible Sources
• Next: Summarizing and Paraphrasing >>
• Last Updated: Jun 18, 2024 4:44 PM
• URL: https://guides.rasmussen.edu/research-papers

Reference Examples

More than 100 reference examples and their corresponding in-text citations are presented in the seventh edition Publication Manual . Examples of the most common works that writers cite are provided on this page; additional examples are available in the Publication Manual .

To find the reference example you need, first select a category (e.g., periodicals) and then choose the appropriate type of work (e.g., journal article ) and follow the relevant example.

When selecting a category, use the webpages and websites category only when a work does not fit better within another category. For example, a report from a government website would use the reports category, whereas a page on a government website that is not a report or other work would use the webpages and websites category.

Also note that print and electronic references are largely the same. For example, to cite both print books and ebooks, use the books and reference works category and then choose the appropriate type of work (i.e., book ) and follow the relevant example (e.g., whole authored book ).

Examples on these pages illustrate the details of reference formats. We make every attempt to show examples that are in keeping with APA Style’s guiding principles of inclusivity and bias-free language. These examples are presented out of context only to demonstrate formatting issues (e.g., which elements to italicize, where punctuation is needed, placement of parentheses). References, including these examples, are not inherently endorsements for the ideas or content of the works themselves. An author may cite a work to support a statement or an idea, to critique that work, or for many other reasons. For more examples, see our sample papers .

Reference examples are covered in the seventh edition APA Style manuals in the Publication Manual Chapter 10 and the Concise Guide Chapter 10

Related handouts

• Common Reference Examples Guide (PDF, 147KB)
• Reference Quick Guide (PDF, 225KB)

Textual Works

Textual works are covered in Sections 10.1–10.8 of the Publication Manual . The most common categories and examples are presented here. For the reviews of other works category, see Section 10.7.

• Journal Article References
• Magazine Article References
• Newspaper Article References
• Blog Post and Blog Comment References
• UpToDate Article References
• Book/Ebook References
• Diagnostic Manual References
• Children’s Book or Other Illustrated Book References
• Classroom Course Pack Material References
• Religious Work References
• Chapter in an Edited Book/Ebook References
• Dictionary Entry References
• Wikipedia Entry References
• Report by a Government Agency References
• Report with Individual Authors References
• Brochure References
• Ethics Code References
• Fact Sheet References
• ISO Standard References
• Press Release References
• White Paper References
• Conference Presentation References
• Conference Proceeding References
• Published Dissertation or Thesis References
• Unpublished Dissertation or Thesis References
• ERIC Database References
• Preprint Article References

Data and Assessments

Data sets are covered in Section 10.9 of the Publication Manual . For the software and tests categories, see Sections 10.10 and 10.11.

• Data Set References
• Toolbox References

Audiovisual Media

Audiovisual media are covered in Sections 10.12–10.14 of the Publication Manual . The most common examples are presented together here. In the manual, these examples and more are separated into categories for audiovisual, audio, and visual media.

• Artwork References
• Clip Art or Stock Image References
• Film and Television References
• Musical Score References
• Online Course or MOOC References
• Podcast References
• PowerPoint Slide or Lecture Note References
• Radio Broadcast References
• TED Talk References
• Transcript of an Audiovisual Work References
• YouTube Video References

Online Media

Online media are covered in Sections 10.15 and 10.16 of the Publication Manual . Please note that blog posts are part of the periodicals category.

• Facebook References
• Instagram References
• LinkedIn References
• Online Forum (e.g., Reddit) References
• TikTok References
• X References
• Webpage on a Website References
• Clinical Practice References
• Open Educational Resource References
• Whole Website References

• Open access
• Published: 11 June 2024

Estimating the causal effects of income on health: how researchers’ definitions of “income” matter

• Erik Igelström 1 ,
• Daniel Kopasker 1 ,
• Peter Craig 1 ,
• Jim Lewsey 2 &
• Srinivasa Vittal Katikireddi 1  

BMC Public Health volume  24 , Article number:  1572 ( 2024 ) Cite this article

216 Accesses

Metrics details

There is a well-established cross-sectional association between income and health, but estimates of the causal effects of income vary substantially. Different definitions of income may lead to substantially different empirical results, yet research is often framed as investigating “the effect of income” as if it were a single, easily definable construct.

Methods/Results

The aim of this paper is to introduce a taxonomy for definitional and conceptual issues in studying individual- or household-level income for health research. We focus on (1) the definition of the income measure (earned and unearned; net, gross, and disposable; real and nominal; individual and household; relative and absolute income) and (2) the definition of the causal contrast (amount, functional form assumptions/transformations, direction, duration of change, and timing of exposure and follow-up). We illustrate the application of the taxonomy to four examples from the published literature.

Conclusions

Quantified estimates of causal effects of income on health and wellbeing have crucial relevance for policymakers to anticipate the consequences of policies targeting the social determinants of health. However, much prior evidence has been limited by lack of clarity in distinguishing between different causal questions. The present framework can help researchers explicitly and precisely articulate income-related exposures and causal questions.

Peer Review reports

Introduction

Socioeconomic conditions have a large influence on health and wellbeing, and the social determinants of health are a major focus for both public health research and policymaking [ 1 , 2 ]. In particular, there is a well-established association between income and many health outcomes, and evidence that changes in income can change health [ 3 , 4 , 5 , 6 ]. However, reported estimates of the causal effects of income on health vary substantially.

Different definitions of income (for example, individual versus household income) may lead to substantially different empirical results [ 7 ]. Despite this, many studies have been framed as investigating “the effect of income” as if it were a single, easily definable construct, without recognising these nuances and their implications for the generalisability and transferability of results. This makes it difficult to understand whether heterogeneity between studies reflects genuine differences between populations or contexts, or merely different methodological and definitional choices.

To address this difficulty, we present a taxonomy for definitional and conceptual issues to consider when studying income as an epidemiological exposure, and discuss their implications in terms of psychosocial and material pathways from income to health [ 8 ]. Our discussion of these issues is structured around (1) how income is measured, and (2) how the causal contrast is defined (Fig.  1 ). We illustrate the use of this taxonomy by applying it to four published studies. We limit the scope to individual- or household-level income; hence, we are not considering the effects of area-level income characteristics on both individual and area-level health.

Visual overview of key definitional and conceptual issues in studying individual- or household-level income as an epidemiological exposure

Defining the income measure

The first issue to consider is how income is being defined. Differently defined measures of income are interrelated but not interchangeable, and different types of income are likely to affect health in different ways. It is in this respect similar to many other epidemiological variables, where related variables may be used for similar purposes, but cannot be treated interchangeably. In practice, choices about what measure to use are often dictated by the nature and limitations of the data used, rather than deliberately made by the researcher. This may limit the kinds of questions that can be asked, and it is essential that researchers adopt an appropriate interpretation of results given the available income measures.

Income source

Income data are often disaggregated by income source. It is common to distinguish between earned and unearned income . Earned income encompasses income obtained through the supply of labour, e.g., salaries or wages from employment, or income from business activities or self-employment. Unearned income in principle encompasses all other sources, including government benefits, income from investments or property (such as interest, dividends, rent, and capital gains), retirement income, inheritances, lottery winnings, and gifts. The nature of the data source will also affect what income sources are captured: for example, tax register data may only encompass reported taxable income, and thus omit informal, illegal, non-monetary or otherwise unrecorded receipts. When income is self-reported, the context and nature of the question asked will also affect the income sources a respondent considers and the accuracy of their response.

Neoclassical economic theory generally assumed that money is a fungible resource, and hence that a rational person would make the same decisions in response to a given amount of income regardless of the source. However, this is often not the case in reality: the “mental accounting” processes that underlie economic decisions are now appreciated to be more complex [ 9 ]. For example, if a cash transfer is labelled as being for a specific purpose, it may be more likely to be used for that purpose [ 10 ], and windfall income may be spent differently from regular or expected income [ 9 ]. The practical upshot of this is that the causal effects of two different interventions on income might differ depending on the type of income targeted, even if the amounts are identical.

Costs deducted: gross, net, and disposable income

A person’s gross income is their total income from all sources, prior to taxes being deducted. For many material pathways to health, such as a person’s ability to buy nutritious food or engage in leisure activities, what matters is not necessarily gross income, but how much of it is available to spend.

Net income refers to income after direct taxes have been subtracted (Fig.  2 ). Disposable income is what remains of the disposable income after subtracting non-discretionary costs , which may be defined differently in different contexts and data sources. Non-discretionary costs generally include housing costs (rent or mortgage repayments), and may also include other costs that can be considered necessary or unavoidable: for example, repayments of non-housing debt (including student debt), utilities, food, transport, healthcare, and clothing (sometimes including for dependents). All other costs are considered discretionary. Although these terms seem to imply a normative judgement, the distinction is typically drawn in a coarse and arbitrary way, and does not necessarily reflect what individuals in a given context genuinely consider unavoidable or dispensable [ 11 ]. They are thus often best viewed as purely technical terms, whose precise meaning needs to be specified.

Illustration of how income measures can be constructed by combining or subtracting other measures

Adjustment for inflation: real and nominal income

When comparing amounts of money over time, it is generally necessary to consider inflation – that is, the rate at which the prices of goods and services change over time. Measures of real income have been adjusted for inflation, such that a change reflects a genuine change in “purchasing power” (i.e., the amount of goods and services that can be obtained with a given amount). Real amounts are generally expressed in terms of the equivalent monetary amount in some given baseline year (e.g. “2010 US dollars”). The unadjusted amount is called nominal income . When comparing incomes across multiple time points, it is typically more appropriate to use a measure of real rather than nominal income.

Real or inflation-adjusted amounts are calculated with reference to a price index, which may be based on macroeconomic measures such as gross domestic product or the price of a fixed set of goods and services [ 12 ]. While these measures describe general trends in price changes, the extent of inflation is often different across different goods and services, and the impact can differ across population groups: for example, increases in food and energy prices may affect low-income households more than high-income households [ 13 ].

Unit of analysis: individual or household

An individual’s own personal income is not always the best way to capture the financial resources they have access to: for example, people may rely on the income of their spouses, parents, children, or others in addition to their own. For this reason, it is often useful to aggregate income by household or some other group. A household is typically defined as a group of people who live in the same dwelling, but more complex definitions may be appropriate depending on the context [ 14 ].

The concept of a household is necessarily simplistic, and does not account for more complex family relationships, such as shared care for children between multiple households. Because of the gendered distribution of both labour market participation and wages, the discrepancy between individual and household income measures is often greater for women [ 7 ]. It is important to consider how the choice of income measure in a study may affect different populations, particularly when stratifying by gender.

Adjustment for household composition

When comparing incomes across households, household size and composition need to be taken into account, since higher income in a larger household may be offset by higher costs. Since these costs do not increase uniformly for each additional person, simply calculating the per capita income is likely to be misleading; instead, equivalisation scales are often used to calculate an equivalised household income based on the number and ages of household members. Multiple such scales are in use [ 15 ]; Table  1 illustrates how equivalised household income is calculated using the modified OECD scale [ 16 ]. Although such standard equivalence scales are widely used, their validity and accuracy in a specific time and place are rarely tested or justified; they may not necessarily reflect true cost differences experienced by households, which are of course highly context-dependent.

Comparison: absolute and relative income

Income can either be measured in absolute terms (i.e., in units of currency) or in relative terms compared to the income distribution in some reference group (for example, income rank or percentile). It has been suggested that relative income, i.e., one’s actual or perceived position in the income distribution, may have an effect on some outcomes (particularly wellbeing) independently of absolute amount [ 17 , 18 ]. Relative income can be expressed in terms of income quantiles (e.g., quintiles, deciles, or percentiles), or by employing a threshold defined in terms of the income distribution: for example, poverty is often defined as an income below some proportion of the median income. The categories defined by quantiles or poverty thresholds are necessarily somewhat arbitrary, and individuals just above or just below a threshold are likely to share a lot of characteristics. Hence it is worth noting that a change in poverty status or income quintile may sometimes represent only a small change in actual circumstances.

Relative and absolute measures of income capture substantially different things, and the difference is particularly relevant when the income distribution itself changes over time. For example, even a large increase in a household’s absolute income would not change that household’s position in the relative income distribution if household income increased by a similar percentage across the population. Whether this property is desirable or not depends entirely on the research question at hand.

Defining the causal contrast

Following dominant practice in epidemiology and quantitative social science, we will assume that a causal effect has to be defined in terms of a causal contrast – intuitively, we must be able to answer the question “the effect of what, compared to what?” [ 19 ]. For a single intervention at a single point in time, the causal contrast is typically between the two potential outcomes where an individual received the intervention and where they did not. Since income varies continuously over a person’s life, the possibilities for defining different causal contrasts are much wider. For time-varying exposures, causal contrasts are typically conceived as comparing two different exposure regimens; i.e., well-defined sequences of exposures [ 20 ]. As with the choice of income measure, we will see that the choice of causal contrast can fundamentally affect which causal mechanisms are involved. In other words, the different causal contrasts implied by different study designs are not merely different strategies for estimating the same “true” causal effect of income, but instead often estimate substantially different effects.

For simplicity, we will mostly describe causal contrasts in this section in terms of income changes ; i.e., increases or decreases that last for a certain length of time. Some prior literature has drawn a distinction between income change and income level, where differences in level represent persistent and often structural inequalities that may affect health in a distinct way [ 21 ]. By using this terminology, we do not mean to suggest that persistent differences in income level are unimportant or should not be regarded as causes. Rather, we propose that for the purpose of defining causal effects, thinking in terms of change promotes clarity. Comparing two individuals whose income level has differed throughout their lives is conceptually different from comparing two individuals whose income levels only recently diverged. Defining causal contrasts in terms of change emphasises the importance of specifying when the counterfactual scenarios diverge. We suggest that the distinction between “level” and “change” is not rigid, and is primarily a question of timescales: while the term “change” implies a short-term exposure and “level” a longer-term difference, both can be understood as referring to different exposure regimens.

Amount, functional form, and transformations

The first feature of an income change that needs to be described is its size. In some settings, such as trials and policy evaluations, the intervention may be an income change of a specific amount. In others, individuals may be exposed to differently sized income changes, and we may want to infer a single effect estimate. We may also need to generalise from the observed changes what effect a differently sized change would have. In all these cases, we need to make assumptions about the functional form of the relationship.

The simplest functional form is a linear relationship, where a £1 change in income would always have the same average effect on health, and, say, a £10 change an effect 10 times as great. This would imply, for example, that a £500 increase in monthly income from £500 to £1,000 would have the same effect on health as an increase from £2,000 to £2,500, and that a £1,000 increase in either situation would have twice that effect. It is clear from both cross-sectional and longitudinal evidence that such a linear relationship is unlikely: additional income appears to make a greater difference to health at the lower end of the income scale [ 22 ]. Hence, it is usually necessary to apply some transformation to an income variable before using it as a predictor in a statistical model.

Perhaps the most commonly used transformation is the logarithm. A change in the logarithm of income (“log income”) represents a percentage change rather than a unit change: for example, an increase of 0.693 in log income corresponds to a doubling in income, regardless of whether this means a change from £100 to £200 or from £5,000 to £10,000. A 0.01 change in log income corresponds to approximately a 1% change in income, 0.02 to approximately 2%, and so forth; however, this rule of thumb becomes increasingly inaccurate at higher percentages.

The interpretations above are applicable when income is first log-transformed, and then the change in log income is calculated. Occasionally, changes in income are calculated first and then log-transformed. Importantly, this “log of change” is mathematically very different from the “change in log”, and cannot be interpreted as straightforwardly.

A well-known limitation of the log transformation is that it cannot be applied to zero or negative values. The inverse hyperbolic sine transformation (arsinh) is sometimes used as an alternative that does not have this limitation. Except for values very close to zero, a change in arsinh-transformed income is nearly identical to the equivalent change in log income, and can be interpreted in the same way.

In practice, visualising the relationship between the transformed or untransformed income variable and the outcome variable (for example, using a binned scatter plot) can be a useful way to assess whether a given transformation is reasonable. If a log or arsinh transformation is insufficient, more complex approaches can be used, including splines, fractional polynomials, or interactions with position in the income distribution. These may allow for more fine-grained or assumption-free analyses, but may also make the interpretation of numerical results more difficult. Reporting predicted probabilities or marginal effects may be more practically useful than regression coefficients.

Regardless of how the functional form of the income–health relationship is represented, we must be careful about generalising beyond the specific, observed circumstances of a study. For example, if a study sample only contained examples of income changes of 1–5%, the study is likely to be informative only about changes of a similar scale, unless we are prepared to make strong assumptions about the functional form beyond the observed values. Although we could, mathematically, report the results in terms of “the effect of a 10% change” (or even greater), we would not necessarily be justified in interpreting them as such.

Direction of change

It may be important to distinguish between income gains and losses. Many analytical approaches rely on the assumption that the positive effect of an increase would be the same size as the negative effect of an equivalent decrease. However, this is unlikely to be true. The asymmetry of gains and losses is a key feature of prospect theory, which focuses on the behavioural responses to anticipated changes [ 23 ]. There is also evidence that income losses have a greater negative impact on health and wellbeing outcomes than the positive impact of income gains [ 6 , 24 , 25 ].

Duration of change

It is also important to consider how long-lasting an income change is. A cash transfer scheme, for example, may have a limited duration (e.g., a single one-off payment, a 12-month period, etc.), or may last indefinitely. Clearly, this distinction becomes increasingly important when the outcome is measured some time after the onset of the exposure, since a longer-lasting payment would add up to a greater total amount. However, the anticipated duration may also be relevant for short-term outcomes. First, an income change that is expected to be temporary may be less beneficial for some mental health outcomes than one that is expected to be permanent. Second, expectations about future income can play a role in decision-making, potentially affecting health-related as well as economic behaviour. Models for explaining such decision-making include the literature on “time discounting” [ 26 ], which focuses on how future expectations affect trade-offs between immediate and delayed gains, and the “permanent income hypothesis”, which holds that consumption behaviour is primarily influenced by one’s expected long-term income rather than actual income in the short term [ 27 ].

Variation and insecurity of income over time may in itself be an important determinant of health [ 28 ]. Various measures of economic insecurity and precarity have been proposed, ranging from subjective measures (such as perceived job security or perceived ability to raise emergency funds when needed) to objective (such as recent experience of a substantial income drop) [ 29 ]. The concept of economic insecurity is inherently related not just to income, but also to other economic variables such as wealth and debt.

Timing of exposure and follow-up

A related but distinct consideration is at what time the outcome is measured relative to the exposure. The true effect of an income change on an outcome measured after ten years may be different from the effect on the same outcome after one year. This may be because the relevant causal mechanisms take time to act, resulting in a delay, or it may be that effects are cumulative, and grow in size after prolonged exposure. For example, cancer mortality rates may take years or decades to respond to a change in income, if the main mechanisms involve changes in other environmental or behavioural exposures, which in turn affect incidence, and only subsequently mortality. On the other hand, mortality due to suicide has been observed to respond rapidly to changes in economic circumstances [ 30 ]. Even outcomes that respond quickly may also be partially mediated by slower mechanisms, in which case longer follow-up times would still be needed to capture the total long-term effects.

The timing of the income change itself during the life course is also important. Changes in household income impact child health outcomes differently and through different mechanisms than adult health [ 5 ]. Most of the available evidence on these impacts relates to health outcomes measured in children or adolescents, for obvious practical reasons: investigating the effect of income in childhood on health in adulthood requires a very long follow-up time. This may often not be practically feasible, and crucially increases the difficulty of drawing causal conclusions from non-experimental study designs.

Further considerations

Wealth and debt.

Separately from income, a person’s financial resources can be measured in terms of wealth. Whereas income denotes the flow of resources received during some time period, wealth denotes the stock of resources owned at a point in time. Wealth can consist of monetary savings, investments such as stocks or bonds, or non-monetary assets such as land and property. Wealth can itself generate income, such as interest, dividends, and rents [ 31 ]; conversely, a surplus of income over time can contribute to one’s wealth. The distribution of wealth may be as important as the distribution of income in explaining health inequalities [ 32 ], but wealth has been less frequently studied, and is less commonly available in administrative or research datasets. Similarly, personal debt appears to be associated with health outcomes [ 33 ], but rigorous causal evidence is lacking and data rarely available.

Public goods

The availability and cost of public goods such as healthcare or social care likely also affects the extent to which income influences health outcomes. A loss of income could more severely limit access to these services in a system that requires payments or insurance cover, compared to one where they are free. Indeed, socioeconomic inequalities in self-reported health and mortality appear to be weaker in countries or regions with well-developed welfare regimes or high expenditure on public goods [ 34 , 35 ].

Co-interventions

Income changes are frequently the result of events that also affect health directly, as well as via their effects on income: individuals may experience job loss, promotion, childbirth, death of a relative, and so on, while societies may undergo policy changes or natural disasters. For virtually any study, it is crucial to consider how much of any effect is attributable to the income change itself, and how much to the event that caused it. For example, when individuals lose income because of a job loss, a substantial proportion of the effect on mental health appears to be attributable to the job loss itself rather than the income loss [ 36 ] (Fig.  3 ).

Illustration of how the effect of income on health can be confounded due to causes of income change that also affect health directly

Interventions in experimental trials or quasi-experimental evaluations may occasionally consist of a cash transfer and little else, but are frequently delivered together with co-interventions (such as training or non-monetary support) or with conditionality requirements (such as job search requirements or compliance with preventive health measures), which may have a substantial independent effect on many outcomes. Natural experiment studies sometimes rely on specific events that caused income changes (such as a recession or natural disaster), and this makes it very difficult to exclude the possibility that any observed effects are due to the event itself rather than the accompanying changes in income [ 37 ].

Reverse causality

A further challenge is reverse causality: health is an important determinant of income, particularly by affecting one’s ability to work, and hence an income change can be both caused by and the cause of changes in health outcomes [ 38 ]. This is a major issue in virtually all observational study designs where the variation in income does not have a random, or at least exogenous, source: although it is most widely acknowledged in the context of cross-sectional studies, it can also be problematic in longitudinal study designs. If both income and health change between two time points, we cannot definitively know which caused which; even if we observe the income change first, we often cannot exclude the possibility that an earlier, unmeasured health factor or event was in fact the cause of both. Natural experiments and instrument-based study designs are particularly important for overcoming this problem, but are relatively underused in public health research [ 39 ].

Applied examples

To illustrate the practical application of our taxonomy, we will consider four studies investigating the effect of income on mental health using contrasting approaches (Table  2 ): a randomised trial of a conditional cash transfer scheme in New York City (study A) [ 40 ]; a natural experiment study based on the introduction of an unconditional cash transfer from casino revenue in North Carolina (study B) [ 41 ]; a fixed-effects panel study using Finnish administrative data on earned and unearned income (study C) [ 42 ]; and a study exploiting random lottery wins in a Swedish sample as a natural experiment (study D) [ 43 ]. We selected these studies to represent some of the most important causal identification strategies in this literature: randomised trial, longitudinal fixed-effects, and a policy-based and a non-policy-based natural experiment. In each of these categories, we selected a study identified in recent systematic reviews as well conducted [ 5 , 6 ]. We prioritised diversity of study design over homogeneity in outcome measure, but all studies use outcomes that can be seen as proxies for general mental health. We will see that each study has made substantively different choices about the measurement and causal contrast, some at the researchers’ discretion, and some enforced by the choice of study design. These choices crucially affect the meaning of the resulting estimates, and the extent to which the studies can be meaningfully compared or generalised.

Considering the definitions of the income measures, perhaps the most salient difference is that each study concerns a substantially different income source. Although both studies A and B concerned transfers of unearned income, the former was conditional and targeted low-income families, while the latter was unconditionally given to all households in a community. Study C instead looked at total taxable income, a large proportion of which would have been earned, while study D used lottery wins, a very specific and unusual type of unearned income. The use of individual income in study C is a potentially consequential decision, and might underestimate the financial resources of individuals who rely on the income of other household members. Accordingly, the authors conducted additional analyses using household income instead of individual income.

The causal contrast is most clearly defined in the studies with a well-defined intervention (A, B, and D), which looked at the effect of receiving versus not receiving a specified amount of additional income. In contrast, study C used all year-on-year changes in taxable income, and therefore both the amount and reason for change are unknown: or, to put it differently, the exposure is a mixture of many different amounts of and reasons for income change. Only the analyses in studies C and D require explicit functional form assumptions, since studies A and B dichotomised the exposure as either receiving or not receiving the intervention. In study D, the functional form assumptions become particularly important, since the lottery wins studied included very large amounts, in many cases orders of magnitude greater than the median income, and considerably greater than the size of the cash transfers in the other studies. It is perhaps questionable whether these quantitative effect estimates can be meaningfully compared when the exposures are so different. However, insofar as we might try to compare them, the comparison hinges on whether the effect of a massive income gain has a straightforward (say, log-linear) relationship with the effect of a more modest one.

The duration of the income changes varies widely: the cash transfer scheme in study A was a time-limited pilot, and the lottery wins in study D largely one-off windfalls; only study B represents a change that participants may plausibly have seen as stable in the long term. Study C, again, illustrates the challenge in clearly stating the causal contrast when the exposure is within-person changes broadly defined: these may be a mixture of temporary and permanent, expected and unexpected changes, but the analysis cannot distinguish these.

Follow-up time also varies widely: the exceptionally long follow-up of study D is a consequence of its unusual identification strategy (exploiting the intrinsic randomisation of a lottery) and its use of administrative data. Studies A and C are more representative of a large proportion of the existing literature, where follow-up length is limited by practical or methodological considerations: in the former, attrition and the costs of running a formal trial, and in the latter, the limitations of the identification strategy (since confounding and other biases would gradually drown out the true effect if the follow-up time were increased).

With these differences made explicit, it becomes clear that we should not expect the results of such disparate studies to converge on any single answer – even when we only consider the issues of income definition and causal contrast, and no other contextual factors that we would expect to cause additional heterogeneity. This exercise thus underscores the importance for studies to report the exposure clearly so that relevant distinctions are clear to readers [ 44 ]. We can also note that among these examples, study B was the only instance of a stable, permanent income increase, and the only study where exposure occurred during childhood. As previously discussed, there are sound theoretical reasons to expect effects on health in those circumstances to be larger. In contrast, much of the existing literature concerns relatively short-term effects of temporary income changes in adult populations [ 6 ].

Concluding remarks

Income as an epidemiological exposure is not a single, well-defined construct. The definitions of “income” and “income change” that any given study uses are not just pragmatic methodological choices, but fundamentally affect what causal pathways we can expect to be involved. Thus, we should expect to find different “causal effects of income” depending on the definitions adopted, even within unbiased studies of the same population. This source of heterogeneity has often been ignored, but has been increasingly highlighted in recent research [ 5 , 7 ].

Causal inference literature generally holds that causal effects can only be estimated for exposures that are consistent , i.e., that do not occur in multiple variations with different causal effects [ 45 ]. It can be argued that income as an exposure violates this consistency criterion in many practical applications [ 46 , 47 ]. However, income is not unique in this respect. A strong argument can be made that no epidemiological exposure satisfies the consistency assumption in the strictest sense, and rather that variations in some aspect or other can always be identified [ 47 ]. It is up to the researcher to determine which kinds of variation are problematic. Rather than simply trying to minimise consistency violations, it is perhaps more important to be clear and explicit about what different kinds of exposures and causal contrasts an estimate incorporates, how they are likely to differ, and how these differences are likely to affect the result.

The taxonomy presented here can be used to assess how far effect estimates from a given study are applicable in a given context, to clarify systematically why they might not apply, and hence to identify evidence gaps that need to be addressed. The examples discussed here illustrate that some of the more common types of evidence may be inadequate to understand the effect of persistent long-term income changes, slow-acting pathways, and long-term effects of childhood exposures.

Recent systematic reviews have made progress in explaining heterogeneity in existing evidence using subgroup analysis and meta-regression [ 5 , 6 ]. We hope this framework will inform and inspire further efforts at evidence synthesis and triangulation, where methodological variety can be harnessed as a source of information rather than seen only as a source of uncertainty [ 48 , 49 ]. Above all, we encourage researchers to aid in these efforts by being as precise as possible when defining income measures and causal contrasts in future empirical studies.

Availability of data and materials

No datasets were generated or analysed during the current study.

CSDH. Closing the gap in a generation: health equity through action on the social determinants of health. Final Report of the Commission on Social Determinants of Health. Geneva: World Health Organization; 2008. https://www.who.int/publications/i/item/9789241563703 .

Marmot M. Social determinants of health inequalities. Lancet. 2005;365(9464):1099–104. https://doi.org/10.1016/S0140-6736(05)71146-6 .

Article   PubMed   Google Scholar  

Imlach Gunasekara F, Carter K, Blakely T. Change in income and change in self-rated health: systematic review of studies using repeated measures to control for confounding bias. Soc Sci Med. 2011;72(2):193–201. https://doi.org/10.1016/j.socscimed.2010.10.029 .

Article   Google Scholar  

Cooper K, Stewart K. Does money in adulthood affect adult outcomes? York: Joseph Rowntree Foundation; 2015. https://www.jrf.org.uk/work/does-money-in-adulthood-affect-adult-outcomes .

Cooper K, Stewart K. Does household income affect children’s outcomes? A systematic review of the evidence. Child Ind Res. 2020;14:981–1005. https://doi.org/10.1007/s12187-020-09782-0 .

Thomson RM, Igelström E, Purba AK, Shimonovich M, Thomson H, McCartney G, et al. How do income changes impact on mental health and wellbeing for working-age adults? A systematic review and meta-analysis. Lancet Public Health. 2022;7(6):e515–28. https://doi.org/10.1016/S2468-2667(22)00058-5 .

Article   PubMed   PubMed Central   Google Scholar  

Shi J, Tarkiainen L, Martikainen P, van Raalte A. The impact of income definitions on mortality inequalities. SSM Popul Health. 2021;15:100915. https://doi.org/10.1016/j.ssmph.2021.100915 .

Marmot M. Psychosocial and material pathways in the relation between income and health: a response to Lynch et al. 2001;322(7296):1233–6. https://doi.org/10.1136/bmj.322.7296.1233 .

Article   CAS   Google Scholar  

Thaler RH. Mental accounting matters. J Behav Decis Making. 1999;12(3):183–206. https://doi.org/10.1002/(SICI)1099-0771(199909)12:33.0.CO;2-F .

Beatty TKM, Blow L, Crossley TF, O’Dea C. Cash by any other name? Evidence on labeling from the UK Winter Fuel Payment. J Public Econ. 2014;118:86–96. https://doi.org/10.1016/j.jpubeco.2014.06.007 .

Banerjee AV, Duflo E. Poor economics: a radical rethinking of the way to fight global poverty. 1st ed. New York: PublicAffairs; 2011.

Google Scholar  

Turner HC, Lauer JA, Tran BX, Teerawattananon Y, Jit M. Adjusting for inflation and currency changes within health economic studies. Value Health. 2019;22(9):1026–32. https://doi.org/10.1016/j.jval.2019.03.021 .

Chapman N, Saeed H, Arthur-Eaton C, O'Connor J. Inflation and the Cost of Living for Household Groups, UK: October 2022. Office for National Statistics; 2022. https://www.ons.gov.uk/economy/inflationandpriceindices/articles/inflationandthecostoflivingforhouseholdgroups/october2022 . Accessed 19 Mar 2024.

Beaman L, Dillon A. Do household definitions matter in survey design? Results from a randomized survey experiment in Mali. J Dev Econ. 2012;98(1):124–35. https://doi.org/10.1016/j.jdeveco.2011.06.005 .

Chanfreau J, Burchardt T. Equivalence scales: rationales, uses and assumptions. Edinburgh: Scottish Government; 2008. https://www.gov.scot/publications/equivalence-scales/ .

Hagenaars A, de Vos K, Zaidi MA. Poverty statistics in the late 1980s: research based on micro-data. Luxembourg: Office for Official Publications of the European Communities; 1994. https://op.europa.eu/en/publication-detail/-/publication/9c787f17-acb6-4f4b-badc-49a2310e65f7 .

Diener E, Sandvik E, Seidlitz L, Diener M. The relationship between income and subjective well-being: relative or absolute? Soc Indic Res. 1993;28(3):195–223. https://doi.org/10.1007/BF01079018 .

Subramanian SV, Kawachi I. Being well and doing well: on the importance of income for health. Int J Soc Welf. 2006;15(s1):S13–22. https://doi.org/10.1111/j.1468-2397.2006.00440.x .

Igelström E, Craig P, Lewsey J, Lynch J, Pearce A, Katikireddi SV. Causal inference and effect estimation using observational data. J Epidemiol Community Health. 2022;76(11):960–6. https://doi.org/10.1136/jech-2022-219267 .

Mansournia MA, Etminan M, Danaei G, Kaufman JS, Collins G. Handling time varying confounding in observational research. BMJ. 2017;359:j4587. https://doi.org/10.1136/bmj.j4587 .

Benzeval M, Judge K. Income and health: the time dimension. Soc Sci Med. 2001;52(9):1371–90. https://doi.org/10.1016/S0277-9536(00)00244-6 .

Article   CAS   PubMed   Google Scholar  

Benzeval M, Judge K, Shouls S. Understanding the relationship between income and health: how much can be gleaned from cross-sectional data? Soc Policy Admin. 2001;35(4):376–96. https://doi.org/10.1111/1467-9515.00240 .

Kahneman D, Tversky A. Prospect theory: an analysis of decision under risk. In: MacLean LC, Ziemba WT, editors. Handbook of the Fundamentals of Financial Decision Making. Singapore: World Scientific; 2013. p. 99–127. https://doi.org/10.1142/9789814417358_0006 .

Fang Z, Niimi Y. Does everyone exhibit loss aversion? Evidence from a panel quantile regression analysis of subjective well-being in Japan. J Jpn Int Econ. 2017;46:79–90. https://doi.org/10.1016/j.jjie.2017.10.003 .

Boyce CJ, Wood AM, Banks J, Clark AE, Brown GDA. Money, well-being, and loss aversion: does an income loss have a greater effect on well-being than an equivalent income gain? Psychol Sci. 2013;24(12):2557–62. https://doi.org/10.1177/0956797613496436 .

Frederick S, Loewenstein G, O’Donoghue T. Time discounting and time preference: a critical review. J Econ Lit. 2002;40(2):351–401. https://doi.org/10.1257/jel.40.2.351 .

Friedman M. The permanent income hypothesis. In: Theory of the consumption function. Princeton: Princeton University Press; 1957. https://doi.org/10.1515/9780691188485 .

Kopasker D, Montagna C, Bender KA. Economic insecurity: a socioeconomic determinant of mental health. SSM Popul Health. 2018;6:184–94. https://doi.org/10.1016/j.ssmph.2018.09.006 .

Richiardi MG, He Z. Measuring economic insecurity: a review of the literature. CeMPA Working Paper 1/20. Essex: Institute for Social and Economic Research, University of Essex. https://www.iser.essex.ac.uk/research/publications/working-papers/cempa/cempa1-20 .

Stuckler D, Reeves A, Loopstra R, Karanikolos M, McKee M. Austerity and health: the impact in the UK and Europe. Eur J Public Health. 2017;27(suppl_4):18–21. https://doi.org/10.1093/eurpub/ckx167 .

Sayer A, McCartney G. Economic relationships and health inequalities: improving public health recommendations. Public Health. 2021;199:103–6. https://doi.org/10.1016/j.puhe.2021.08.017 .

Katikireddi SV, Niedzwiedz CL, Dundas R, Kondo N, Leyland AH, Rostila M. Inequalities in all-cause and cause-specific mortality across the life course by wealth and income in Sweden: a register-based cohort study. Int J Epidemiol. 2020;49(3):917–25. https://doi.org/10.1093/ije/dyaa053 .

Richardson T, Elliott P, Roberts R. The relationship between personal unsecured debt and mental and physical health: a systematic review and meta-analysis. Clin Psychol Rev. 2013;33(8):1148–62. https://doi.org/10.1016/j.cpr.2013.08.009 .

Eikemo TA, Bambra C, Joyce K, Dahl E. Welfare state regimes and income-related health inequalities: a comparison of 23 European countries. Eur J Public Health. 2008;18(6):593–9. https://doi.org/10.1093/eurpub/ckn092 .

Dunn JR, Burgess B, Ross NA. Income distribution, public services expenditures, and all cause mortality in US states. J Epidemiol Commun H. 2005;59(9):768–74. https://doi.org/10.1136/jech.2004.030361 .

Thomson RM, Kopasker D, Leyland A, Pearce A, Katikireddi SV. To what extent does income explain the effect of unemployment on mental health? Mediation analysis in the UK Household Longitudinal Study. Psychol Med. 2022;53(13):6271–9. https://doi.org/10.1017/S0033291722003580 .

Rosenzweig MR, Wolpin KI. Natural “natural experiments” in economics. J Econ Lit. 2000;38(4):827–74. https://doi.org/10.1257/jel.38.4.827 .

Harrison S, Davies AR, Dickson M, Tyrrell J, Green MJ, Katikireddi SV, et al. The causal effects of health conditions and risk factors on social and socioeconomic outcomes: Mendelian randomization in UK Biobank. Int J Epidemiol. 2020;49(5):1661–81. https://doi.org/10.1093/ije/dyaa114 .

Matthay EC, Hagan E, Gottlieb LM, Tan ML, Vlahov D, Adler NE, et al. Alternative causal inference methods in population health research: evaluating tradeoffs and triangulating evidence. SSM Popul Health. 2020;10:100526. https://doi.org/10.1016/j.ssmph.2019.100526 .

Courtin E, Muennig P, Verma N, Riccio JA, Lagarde M, Vineis P, et al. Conditional cash transfers and health of low-income families in the US: evaluating the Family Rewards experiment. Health Aff. 2018;37(3):438–46. https://doi.org/10.1377/hlthaff.2017.1271 .

Akee R, Copeland W, Costello EJ, Simeonova E. How does household income affect child personality traits and behaviors? Am Econ Rev. 2018;108(3):775–827. https://doi.org/10.1257/aer.20160133 .

Junna L, Moustgaard H, Tarkiainen L, Martikainen P. The association between income and psychotropic drug purchases: individual fixed effects analysis of annual longitudinal data in 2003–2013. Epidemiology. 2019;30(2):221–9. https://doi.org/10.1097/EDE.0000000000000956 .

Lindqvist E, Östling R, Cesarini D. Long-run effects of lottery wealth on psychological well-being. Rev Econ Stud. 2020;87(6):2703–26. https://doi.org/10.1093/restud/rdaa006 .

Campbell M, Katikireddi SV, Hoffmann T, Armstrong R, Waters E, Craig P. TIDieR-PHP: a reporting guideline for population health and policy interventions. BMJ. 2018;360:k1079. https://doi.org/10.1136/bmj.k1079 .

Cole SR, Frangakis CE. The consistency statement in causal inference: a definition or an assumption? Epidemiology. 2009;20(1):3–5. https://doi.org/10.1097/EDE.0b013e31818ef366 .

Rehkopf DH, Glymour MM, Osypuk TL. The consistency assumption for causal inference in social epidemiology: when a rose is not a rose. Curr Epidemiol Rep. 2016;3(1):63–71. https://doi.org/10.1007/s40471-016-0069-5 .

Hernán MA. Does water kill? A call for less casual causal inferences. Ann Epidemiol. 2016;26(10):674–80. https://doi.org/10.1016/j.annepidem.2016.08.016 .

Lawlor DA, Tilling K, Davey Smith G. Triangulation in aetiological epidemiology. Int J Epidemiol. 2017;45(6):1866–86. https://doi.org/10.1093/ije/dyw314 .

Article   PubMed Central   Google Scholar  

Munafò MR, Davey Smith G. Robust research needs many lines of evidence. Cah Rev The. 2018;553(7689):399–401. https://doi.org/10.1038/d41586-018-01023-3 .

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EI, DK, PC, and SVK receive funding from the Medical Research Council (MC_UU_00022/2) and the Scottish Government Chief Scientist Office (SPHSU17). DK and SVK receive funding from the European Research Council (949582).

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Igelström, E., Kopasker, D., Craig, P. et al. Estimating the causal effects of income on health: how researchers’ definitions of “income” matter. BMC Public Health 24 , 1572 (2024). https://doi.org/10.1186/s12889-024-19049-w

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Iago’s isolation from humanity is ideological and emotional hermitry rather than physical solitariness: he detaches himself from social standards and practices, but continues to weave his diabolical influence as a player in the [...]

Speech in Shakespeare's "Othello" possesses a power beyond that of deeds'. It is Othello's fantastical storytelling that won him Desdemona at the start, Iago's poisonous suggestion that leads the general to murder his own wife, [...]

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